.github: Cancel outdated PR and push workflows

When updating a pull request, workflows associated with the previous
version continue to run. A way to prevent that and cancel outdated
workflows is to use concurrency groups.

This commit handles workflows triggered by pull requests and pushes.
We define each concurrency group such that they are unique to the
pull request (via PR number) if triggered by event pull_request or
to the commit (via SHA) if triggered by event push.

Signed-off-by: Paul Chaignon <paul@cilium.io>

.github/workflows/codeql-analysis.yml

@@ -1,5 +1,6 @@
 name: codeql
 
+# Any change in triggers needs to be reflected in the concurrency group.
 on:
   push:
     branches:
@@ -13,6 +14,10 @@ on:
   schedule:
     - cron: "45 7 * * 3"
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.event.after || 'scheduled' }}
+  cancel-in-progress: true
+
 jobs:
   analyze:
     if: github.repository == 'cilium/hubble'

.github/workflows/tests.yml

@@ -1,4 +1,6 @@
 name: Run static checks and unit tests
+
+# Any change in triggers needs to be reflected in the concurrency group.
 on:
   push:
     branches:
@@ -8,6 +10,11 @@ on:
     branches:
     - master
     - v*
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.event.after }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest