Allow not updating the config file, even when it exists.

[coderanger]

This allows working completely off the latest tag support for current_version so the config file doesn't change on bump.

[coderanger]

Any chance of this getting looked at?

[florisla]

This should also be updated in the README.

[florisla]

Can we bypass _update_config_file altogether in case of no_update_config ?

[coderanger]

Could do that too, would you prefer that? Was trying to avoid flow changes as much as possible.

[florisla]

Does this not bring the version in the config out of sync with the other version numbers?

[coderanger]

The goal was to better help with a tag-only workflow. So a config like:

[bumpversion]
commit = True
tag = True
no_update_config = True
parse = (?P<major>\d+)\.(?P<minor>\d+)
serialize = {major}.{minor}

With no current_version at all, and the version discovered only from the latest tag on the fly.

[florisla]

OK. Do you think it's possible to have no no_update_configat all option, and just assume this in case we can't find a current_version in the config or in the command-line arguments?