Modify versioningit format to use committer date

[backmari]

Short description of the changes:

Revert the change to ignore RC version tags in versioningit, since they were also ignored when building RC packages. Instead ensure the dev versions increase monotonically by using timestamp rather than number of commits since the latest tag.

Check list for the pull request

• I have read the [CONTRIBUTING]
• I have read the [CODE_OF_CONDUCT]
• I have added tests for my changes
• I have updated the documentation accordingly

Check list for the reviewer

• I have read the [CONTRIBUTING]
• I have verified the proposed changes
• best software practices
  • all internal functions have an underbar, as is python standard
  • clearly named variables (better to be verbose in variable names)
  • code comments explaining the intent of code blocks
• All the tests are passing
• The documentation is up to date
• code comments added when explaining intent

Manual test for the reviewer

References