Added .editorconfig
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24042?src=pr&el=h1) Report
> Merging [#24042](https://codecov.io/gh/pandas-dev/pandas/pull/24042?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/b45eb265dd88648fb02ebb0fdcfb168364ab664e?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/24042/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24042?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #24042   +/-   ##
=======================================
  Coverage   42.46%   42.46%           
=======================================
  Files         161      161           
  Lines       51557    51557           
=======================================
  Hits        21892    21892           
  Misses      29665    29665
```

| Flag | Coverage Δ | |
|---|---|---|
| #single | `42.46% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24042?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/24042?src=pr&el=footer). Last update [b45eb26...02404e5](https://codecov.io/gh/pandas-dev/pandas/pull/24042?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/24042?src=pr&el=h1) Report
> Merging [#24042](https://codecov.io/gh/pandas-dev/pandas/pull/24042?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/b45eb265dd88648fb02ebb0fdcfb168364ab664e?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/24042/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24042?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #24042   +/-   ##
=======================================
  Coverage   42.46%   42.46%           
=======================================
  Files         161      161           
  Lines       51557    51557           
=======================================
  Hits        21892    21892           
  Misses      29665    29665
```

| Flag | Coverage Δ | |
|---|---|---|
| #single | `42.46% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24042?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/24042?src=pr&el=footer). Last update [b45eb26...02404e5](https://codecov.io/gh/pandas-dev/pandas/pull/24042?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 What's this for? Most editors will recognize the settings in our setup.cfg. >Most editors will recognize the settings in our setup.cfg.

Most editors don't support `setup.cfg`. `.editorconfig` is a language-invariant way widely supported by editors. -1 on this

@KOLANICH can you provide information on which scenario this could be useful? Contributing using Notepad++ as an editor. xref https://github.com/matplotlib/matplotlib/pull/12922 https://github.com/scipy/scipy/pull/9560 https://github.com/scikit-learn/scikit-learn/pull/12710 and 18 others (see https://github.com/KOLANICH ).

I am :-1: on this (both here and else where). thanks for the heads up @tacaswell 