Allow to release major version tag

[mgoltzsche]

To maintain an sv4git GitHub Action, I would like to create a git tag for the major version in addition to the full semantic version one, overwriting the existing one if any. However, when I add the major version tag manually, subsequent release versions always start counting at the last major version tag, breaking version increments permanently, unless I remove the major version tag again.

Example:

1. Release for feat commit: New version is 0.1.0, tags v0.1.0 and v0 were created.
2. Release for feat commit: New version is 0.1.0 again!

[mgoltzsche]

I realize that v* tags can be ignored by configuring tag.filter=v*.*.* :sweat_smile:.

[mgoltzsche]

Wouldn't it make sense to make that the default?