[docs] use `versionadded`, `versionchanged` and `deprecated` directive

[ydcjeff]

🚀 Feature

Use .. versionadded::, .. versionchanged:: and .. deprecated:: directive, so that user knows which features are added / changed / deprecated in which version and they can navigate the docs easily without changing the docs from version to version.

Ref: https://www.sphinx-doc.org/en/master/usage/restructuredtext/directives.html#directive-versionadded

[vfdev-5]

Thanks for the idea @ydcjeff ! It would be very nice to have that.

[ydcjeff]

@vfdev-5 we can start adding for features to be added in 0.5.0.

Where should we begin?

[vfdev-5]

Yes, starting from v0.5.0 sounds good. Maybe later we can add other marks for v0.4.0 as well.

[vfdev-5]

@ydcjeff could you please mention those versionadded, versionchanged in the CONTRIBUTING in the docs section. Thanks !

[ydcjeff]

This is already in use, so closing