How to detect in git whether the new branch has a commit?

Question

What I require:

• master branch is the main branch.
• Now I create a branch 1-my-new-issue from master.
• master has now moved ahead, it actually may or may not move ahead, it doesn't matter.
• I want to detect, whether my branch 1-my-new-issue has any new commit.

To avoid this being a XY problem, why i want this:

• I am using GitlabCI
• Pipelines automatically run in a issue branch even though there is no new commit on the branch.
• I want to avoid running pipelines when there is no change to this branch from the point it was checked out from master.

From what I know gitlab ci provides no known way to do this, so I was thinking if I could detect it using git then I can simply skip the job.