BUG: Period.__eq__ numpy scalar (#44182 (comment))
- [x] fixes https://github.com/pandas-dev/pandas/pull/44182#issuecomment-956851322
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit) for how to run them
- [ ] whatsnew entry


I added three tests but only one of them fails without the code change.

Fixed by the code update:
```python
Period("2000-01", "M") == np.array(0)
```

Additional tests not affected by the code update:
```python
idx = period_range("2007-01", periods=20, freq="M")
idx == np.array(idx[10])

Period("2000-01", "M") == np.int_(0)
```

 This used to return `True` (but now returns `False`), so I think we are not yet entirely there:

```python
p = pd.Period("2000-01", "M")
p == np.array(p)
``` thanks @mathause 