Fixed interpolate function
- [X] closes #25190 
- [X] tests added
- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [X] whatsnew entry in 0.25.0

Modified `interpolate` function
https://github.com/pandas-dev/pandas/blob/5278cc6dc674c225c204532aeedca9df342f67c7/pandas/core/generic.py#L6785

### Fixes
- Checking axis for `0` and `'index'` as well as `1` and `'columns'`
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25210?src=pr&el=h1) Report
> Merging [#25210](https://codecov.io/gh/pandas-dev/pandas/pull/25210?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/5278cc6dc674c225c204532aeedca9df342f67c7?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/25210/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25210?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25210   +/-   ##
=======================================
  Coverage   92.34%   92.34%           
=======================================
  Files         166      166           
  Lines       52314    52314           
=======================================
  Hits        48311    48311           
  Misses       4003     4003
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.78% <100%> (ø)` | :arrow_up: |
| #single | `42.84% <0%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25210?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/25210/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `96.39% <100%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25210?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/25210?src=pr&el=footer). Last update [5278cc6...6e0cff6](https://codecov.io/gh/pandas-dev/pandas/pull/25210?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/25210?src=pr&el=h1) Report
> Merging [#25210](https://codecov.io/gh/pandas-dev/pandas/pull/25210?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4d44a2aff08c3075d9472e361bd7448a0472494e?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/25210/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25210?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #25210      +/-   ##
==========================================
+ Coverage   91.72%   91.72%   +<.01%     
==========================================
  Files         173      173              
  Lines       52831    52832       +1     
==========================================
+ Hits        48457    48459       +2     
+ Misses       4374     4373       -1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.28% <100%> (ø)` | :arrow_up: |
| #single | `41.72% <0%> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25210?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/25210/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `94.16% <100%> (ø)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/25210/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `87.66% <0%> (+0.09%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25210?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/25210?src=pr&el=footer). Last update [4d44a2a...6f63506](https://codecov.io/gh/pandas-dev/pandas/pull/25210?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Hello @Vibhu-Agarwal! Thanks for updating the PR.





Cheers ! There are no PEP8 issues in this Pull Request. :beers: 

##### Comment last updated on February 12, 2019 at 08:33 Hours UTC pls merge master as well @jreback Made all the requested changes. @jreback Please review the requested changes.
- [X] Put my test under previous appropriate header.
https://github.com/pandas-dev/pandas/blob/4d44a2aff08c3075d9472e361bd7448a0472494e/pandas/tests/generic/test_generic.py#L665
- [X] Updated entry in 0.25.0 Pipeline faiure below: @Vibhu-Agarwal mind merging master to see if that resolves this

```
E           CalledProcessError: Command '['C:\\Miniconda\\envs\\pandas-dev\\python.exe', '-OO', '-c', 
'import pandas']' returned non-zero exit status 1
``` if you would like to merge master and update. closing as stale. if you'd like to continue pls ping.