CI: bump numpy on appveyor ci
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/21271?src=pr&el=h1) Report
> Merging [#21271](https://codecov.io/gh/pandas-dev/pandas/pull/21271?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/7647969df247727afdcbcfa52169f4436d6ef377?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/21271/graphs/tree.svg?src=pr&width=650&token=eZ4WkYLtcO&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/21271?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #21271      +/-   ##
==========================================
+ Coverage   91.84%   91.84%   +<.01%     
==========================================
  Files         153      153              
  Lines       49540    49543       +3     
==========================================
+ Hits        45501    45504       +3     
  Misses       4039     4039
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.24% <ø> (ø)` | :arrow_up: |
| #single | `41.87% <ø> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/21271?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/sparse/array.py](https://codecov.io/gh/pandas-dev/pandas/pull/21271/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3BhcnNlL2FycmF5LnB5) | `91.38% <0%> (+0.06%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/21271?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/21271?src=pr&el=footer). Last update [7647969...c48c9ec](https://codecov.io/gh/pandas-dev/pandas/pull/21271?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
