DOC: Link to dev version of contributing guide from README.md
README.md should link to the development version of the contributing guide, since the stable version may not match current practice for `master`. For example, see #24069 .

I'm not sure this PR is a good idea, but I thought it was easiest open it and get comments directly.

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=h1) Report
> Merging [#24172](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/949b1482422dd88db5d039cf38fc19994737bad2?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24172/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24172      +/-   ##
==========================================
+ Coverage   92.21%   92.21%   +<.01%     
==========================================
  Files         162      162              
  Lines       51723    51723              
==========================================
+ Hits        47694    47695       +1     
+ Misses       4029     4028       -1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.61% <ø> (ø)` | :arrow_up: |
| #single | `43.03% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/24172/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `87.41% <0%> (-0.1%)` | :arrow_down: |
| [pandas/io/json/json.py](https://codecov.io/gh/pandas-dev/pandas/pull/24172/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2pzb24vanNvbi5weQ==) | `93.09% <0%> (+0.47%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=footer). Last update [949b148...b5460c3](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=h1) Report
> Merging [#24172](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/949b1482422dd88db5d039cf38fc19994737bad2?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24172/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #24172   +/-   ##
=======================================
  Coverage   92.21%   92.21%           
=======================================
  Files         162      162           
  Lines       51723    51723           
=======================================
  Hits        47694    47694           
  Misses       4029     4029
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.61% <ø> (ø)` | :arrow_up: |
| #single | `43.03% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/24172/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `98.56% <0%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=footer). Last update [949b148...0109662](https://codecov.io/gh/pandas-dev/pandas/pull/24172?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 this would be fine. @jorisvandenbossche @TomAugspurger  Yeah, that's probably best. That link does occasionally break if a build fails, but not too often. There are 3 other places in the repo that could be changed too:

* [.github/CONTRIBUTING.md](https://github.com/pandas-dev/pandas/blob/master/.github/CONTRIBUTING.md#L6) line 6 and line 22
* [doc/README.rst](https://github.com/pandas-dev/pandas/blob/master/doc/README.rst#L1) line 1
* [doc/source/overview.rst](https://github.com/pandas-dev/pandas/blob/master/doc/source/overview.rst#L95) line 95

My inclination is to change the first, but leave the others alone so that internal references in `docs` are maintained. What do you think? I'm also concerned about duplication between `.github/CONTRIBUTING.md` (which I've only just found) and the contributing section of `README.md`. > My inclination is to change the first,

I think you can change the first two (and the third could actually use sphinx syntax to make a link, so it always links to the same version) @jorisvandenbossche are you ok with this now? I think changing the link in overview.rst to be a Sphinx ref makes sense. thanks @jamesmyatt  @jamesmyatt would you be interested in making another PR to update that
last link in contributing.rst?

On Mon, Dec 17, 2018 at 6:56 AM Jeff Reback <notifications@github.com>
wrote:

> thanks @jamesmyatt <https://github.com/jamesmyatt>
>
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 @TomAugspurger , sure.