Remove NDFrame.select
- [x] xref #17633
- [x] whatsnew entry

Removes ``NDFrame.select``, that was deprecated in 0.21.
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26641?src=pr&el=h1) Report
> Merging [#26641](https://codecov.io/gh/pandas-dev/pandas/pull/26641?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/101370645d13e1d0f256f367f4ef56a8329b56b6?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26641/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26641?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26641      +/-   ##
==========================================
- Coverage   91.87%   91.87%   -0.01%     
==========================================
  Files         174      174              
  Lines       50692    50683       -9     
==========================================
- Hits        46575    46563      -12     
- Misses       4117     4120       +3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.41% <ø> (ø)` | :arrow_up: |
| #single | `41.79% <ø> (-0.08%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26641?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/26641/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `93.63% <ø> (+0.02%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26641/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `78.94% <0%> (-10.53%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26641/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97% <0%> (-0.12%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26641?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/26641?src=pr&el=footer). Last update [1013706...64ed9c3](https://codecov.io/gh/pandas-dev/pandas/pull/26641?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/26641?src=pr&el=h1) Report
> Merging [#26641](https://codecov.io/gh/pandas-dev/pandas/pull/26641?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/101370645d13e1d0f256f367f4ef56a8329b56b6?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26641/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26641?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26641      +/-   ##
==========================================
- Coverage   91.87%   91.87%   -0.01%     
==========================================
  Files         174      174              
  Lines       50692    50683       -9     
==========================================
- Hits        46575    46563      -12     
- Misses       4117     4120       +3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.41% <ø> (ø)` | :arrow_up: |
| #single | `41.79% <ø> (-0.08%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26641?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/26641/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `93.63% <ø> (+0.02%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26641/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `78.94% <0%> (-10.53%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26641/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97% <0%> (-0.12%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26641?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/26641?src=pr&el=footer). Last update [1013706...64ed9c3](https://codecov.io/gh/pandas-dev/pandas/pull/26641?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Thanks @topper-123 !