Version flag alongside other commands about python-fire

[jfrost-mo]

The short option should be -V, as -v is usually short for verbose.

Otherwise this would be a great feature, as command --version is a very common pattern on CLI programs for testing if it is installed correctly.

[dbieber]

I would be supportive of a change that makes foo --version in addition to foo -- --version in all cases except where --version is an acceptable flag to foo. However, note that such a change is not currently planned.

[dbieber]

Right now foo --version is not supported but foo -- --version is. The reason we originally chose not to support foo --version is that the function foo could have an argument named version, and in that case it would be a name collision.