GH-44404: [CI] Stop running CI "push" jobs for Dependabot

[kou]

Rationale for this change

They are redundant. We have the same jobs for "push" and "pull_request". We don't need either of them.

What changes are included in this PR?

Ignore dependabot/** branches for "push".

We need to define not only branches: but also tags:. If we don't define tags:, the target workflows aren't trigger by tag push.

See also: https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#onpushbranchestagsbranches-ignoretags-ignore

If you define only tags/tags-ignore or only branches/branches-ignore, the workflow won't run for events affecting the undefined Git ref. If you define neither tags/tags-ignore or branches/branches-ignore, the workflow will run for events affecting either branches or tags. If you define both branches/branches-ignore and paths/paths-ignore, the workflow will only run when both filters are satisfied.

Are these changes tested?

No. Let's try on apache/arrow main.

Are there any user-facing changes?

No.

• GitHub Issue: [CI] Stop running CI "push" jobs for Dependabot #44404

[github-actions]

⚠️ GitHub issue #44404 has been automatically assigned in GitHub to PR creator.

[kou]

Let's try on main.

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 3 benchmarking runs that have been run so far on merge-commit 16ad979.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 6 possible false positives for unstable benchmarks that are known to sometimes produce them.