Working with git tags is very helpful in managing Gitlab releases etc. In fact it is completely independent from Gitlab and comes with the git cli.
git tag -a v1.4 -m "my version 1.4"
There is actually no need to use v1.4, you can very well just using any kine of tag and numbering, including issues, bugfixes etc.
For a regular release I would use
git tag -a 1.0.0 -m "First major release"
git push --tags
for local tags:
git tag -d $(git tag)