torch: Make __version__ better with comparisons (#61556)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/61556
Prior to 1.10.0 `torch.__version__` was stored as a str and so many did
comparisons against `torch.__version__` as if it were a str. In order to not
break them we have TorchVersion which masquerades as a str while also
having the ability to compare against both packaging.version.Version as
well as tuples of values, eg. (1, 2, 1)
Examples:
Comparing a TorchVersion object to a Version object
```
TorchVersion('1.10.0a') > Version('1.10.0a')
```
Comparing a TorchVersion object to a Tuple object
```
TorchVersion('1.10.0a') > (1, 2) # 1.2
TorchVersion('1.10.0a') > (1, 2, 1) # 1.2.1
```
Comparing a TorchVersion object against a string
```
TorchVersion('1.10.0a') > '1.2'
TorchVersion('1.10.0a') > '1.2.1'
```
Resolves https://github.com/pytorch/pytorch/issues/61540
Signed-off-by: Eli Uriegas <eliuriegas@fb.com>
Test Plan: Imported from OSS
Reviewed By: zou3519
Differential Revision: D29671234
Pulled By: seemethere
fbshipit-source-id: 6044805918723b4aca60bbec4b5aafc1189eaad7
