You have to take care about yourself to create a corresponding branch or tag in your VCS whenever you create a new package version.
I would also recommend to use the
--branch parameters to reflect your current snapshot in VCS when using the
force:package:version:create command. These information are visible when executing
sfdx force:package:version:list against your packaging org - so you can see which branch/tag to checkout for each package version.
Just another solution you can try to receive already packaged metadata components:
sfdx force:package:version:list -v [packaging org alias]
- get the package version id you are interested in (starting with 04t)
- install the package in a sandbox/scratch org with
sfdx force:package:install --package 04t... -u [org alias to install]
- retrieve the packaged metadata components with
sfdx force:mdapi:retrieve --singlepackage --retrievetargetdir [dir to store export] --packagenames [your package name] -u [org alias where package is installed]
- unzip your export and convert source into source tracking format
sfdx force:source:convert -r [your source path] -d [destination path]
Now you should have all metadata components from the package in the same format as you packaged it once