[FEATURE] squash bump commits to tidy commit history

[holmesb]

Is your feature request related to a problem? Please describe.
Bump commits (chore(version): bump packages) for every change pollutes the commit history. This is especially true for monorepos with a large number of packages. But without bump commits (disable_bump_commit = true), the change logs aren't committed.

Describe the solution you'd like
Instead of a bump commit for every change, the cog bump --auto command squashes the bump commit it creates into the preceding one. This would have to happen before tagging occurs because the the original commit's hash will change. I propose a new configuration option: squash_bump_commit = true\false, with the default being false. Has no effect if disable_bump_commit = true.

Describe alternatives you've considered
Scripting using post_bump_hooks, but this seems high effort and something useful enough to be built into Cocogitto.