fix: Drop leading `v` in minor image release

What does this MR do?

With !213 (merged) we introduced the minor image release, however we forgot to drop the leading v. This MR fixes that.

What are the relevant issue numbers?

Relates to gitlab-org&4060 (closed)

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug

String substitution test

Testcase

❯ bash test.sh
v1.2.3
v1.2
1.2

Script

❯ cat test.sh
#!/bin/bash

CI_COMMIT_TAG=v1.2.3

rel=${CI_COMMIT_TAG/+*/}

echo $rel

tag=${rel%.*}

echo $tag

tag=${tag/v/}

echo $tag