IONOS(ci): unify concurrency group across push and pull_request runs

Previously the concurrency group used `pr-<num>` for pull_request events
and `<github.ref>` for push events on non-protected branches, so a
`*/dev/*` branch with an open PR produced two parallel runs on every
push: a `push` event run keyed on `refs/heads/<branch>` and a
`pull_request: synchronize` run keyed on `pr-<num>`. Different group
keys meant `cancel-in-progress` never applied between them.

Unify the key to `github.head_ref || github.ref_name` for all non-
protected branches. For pull_request that resolves to the source branch
name; for push it falls back to `ref_name`. Both events now share the
same group and the later-arriving run cancels the older one — in
practice the `pull_request: synchronize` event arrives a few seconds
after `push`, so the PR run wins and remains the PR status check.

Trade-off: `trigger-remote-dev-workflow` is gated to `push` events on
`ionos-dev|ionos-stable|rc/*|*/dev/*`, so it will not fire on dev-branch
pushes while a PR is open from that branch. It still fires on direct
pushes to protected branches (ionos-dev/stable/rc/*), whose group is
keyed per `github.run_id` and therefore never cancels, and on dev-branch
pushes once the PR is closed/merged.

Signed-off-by: Misha M.-Kupriyanov <kupriyanov@strato.de>

Author: printminion-co

.github/workflows/hidrive-next-build.yml

@@ -52,17 +52,18 @@ on:
         type: string
         default: ''
 
+# Concurrency group is intentionally shared between push and pull_request runs
+# of the same source branch, so a `*/dev/*` branch with an open PR does not
+# produce two parallel runs. Protected branches (ionos-dev/stable/rc/*) use a
+# unique-per-run-id key so consecutive pushes never cancel each other.
 concurrency:
   group: >-
     ${{ github.workflow }}-${{
-      github.event_name == 'pull_request' && format('pr-{0}', github.event.pull_request.number) ||
       (
-        (
-          contains(fromJson('["refs/heads/ionos-dev","refs/heads/ionos-stable"]'), github.ref) ||
-          startsWith(github.ref, 'refs/heads/rc/')
-        ) && github.run_id ||
-        github.ref
-      )
+        contains(fromJson('["refs/heads/ionos-dev","refs/heads/ionos-stable"]'), github.ref) ||
+        startsWith(github.ref, 'refs/heads/rc/')
+      ) && github.run_id ||
+      (github.head_ref || github.ref_name)
     }}
   cancel-in-progress: true