remove .github/workflows/pr-title.yml

This is not used and AFAICT has not trigger any actions for a very long
time I guess:
https://github.com/containers/podman/actions/workflows/pr-title.yml

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

.github/workflows/pr-title.yml

@@ -1,24 +0,0 @@
-# Upstream: github.com/tzkhan/pr-update-action
-
-name: "PR title check"
-
-on:
-  pull_request_target:
-    branches:
-      - "!master"   # causes errors; reason unknown
-
-permissions:
-  contents: read
-
-jobs:
-  update_pr:
-    permissions:
-      pull-requests: write  # for tzkhan/pr-update-action to update PRs
-    runs-on: ubuntu-latest
-    steps:
-    - uses: tzkhan/pr-update-action@bbd4c9395df8a9c4ef075b8b7fe29f2ca76cdca9 # v2
-      with:
-        repo-token: "${{ secrets.GITHUB_TOKEN }}"
-        base-branch-regex: '^(?!master).*$'
-        title-template: '[%basebranch%]'
-        title-prefix-space: true