add numpy typing plugin to mypy config (pytorch#92930)

This added the numpy typing plugin to mypy config so that we could
use it for DeviceMesh typing annotations

Please see pytorch#92931 about why we need this. For example, we are currently saving the DeviceMesh's mesh field as torch.Tensor, where when we do sth like:
```python
with FakeTensorMode():
    device_mesh = DeviceMesh("cuda", torch.arange(4))
```
It would throw error because FakeTensorMode or any TorchDispatchMode tracks every tensor creation and interactions. While DeviceMesh just want to save a nd-array to record the mesh topology, and would like to avoid the interaction with subsystems like FakeTensor, so we want to support saving `mesh` as numpy array instead.

Pull Request resolved: pytorch#92930
Approved by: https://github.com/ezyang, https://github.com/malfet

mypy-nofollow.ini

@@ -1,5 +1,5 @@
 [mypy]
-plugins = mypy_plugins/check_mypy_version.py
+plugins = mypy_plugins/check_mypy_version.py, numpy.typing.mypy_plugin
 
 cache_dir = .mypy_cache/nofollow
 warn_unused_configs = True

mypy-strict.ini

@@ -7,7 +7,7 @@
 
 [mypy]
 python_version = 3.8
-plugins = mypy_plugins/check_mypy_version.py
+plugins = mypy_plugins/check_mypy_version.py, numpy.typing.mypy_plugin
 
 cache_dir = .mypy_cache/strict
 strict_optional = True

mypy.ini

@@ -2,7 +2,7 @@
 # test_run_mypy in test/test_type_hints.py uses this string)
 
 [mypy]
-plugins = mypy_plugins/check_mypy_version.py
+plugins = mypy_plugins/check_mypy_version.py, numpy.typing.mypy_plugin
 
 cache_dir = .mypy_cache/normal
 warn_unused_configs = True