Typo: UCT -> UTC
- [(no issue)] closes #xxxx
- [(didn't change code)] tests added / passed
- [(didn't change .py files)] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [(seems unnecessary)] whatsnew entry

LGTM, ping on green. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22548?src=pr&el=h1) Report
> Merging [#22548](https://codecov.io/gh/pandas-dev/pandas/pull/22548?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/1a798be98b7a605693c6d1143ab1d703a77f47a1?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/22548/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22548?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #22548   +/-   ##
=======================================
  Coverage   92.04%   92.04%           
=======================================
  Files         169      169           
  Lines       50783    50783           
=======================================
  Hits        46741    46741           
  Misses       4042     4042
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.45% <ø> (ø)` | :arrow_up: |
| #single | `42.22% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22548?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/22548?src=pr&el=footer). Last update [1a798be...a974cb3](https://codecov.io/gh/pandas-dev/pandas/pull/22548?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 🍏  thanks!