chore: Update smb-kerberos workflow

Signed-off-by: Louis Chemineau <louis@chmn.me>

.github/workflows/smb-kerberos.yml

@@ -1,20 +1,17 @@
 name: Samba Kerberos SSO
 on:
-  push:
-    branches:
-      - master
-      - stable*
-    paths:
-      - 'apps/files_external/**'
-      - '.github/workflows/smb-kerberos.yml'
   pull_request:
     paths:
       - 'apps/files_external/**'
       - '.github/workflows/smb-kerberos.yml'
 
+concurrency:
+  group: smb-kerberos-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   smb-kerberos-tests:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
 
     if: ${{ github.repository_owner != 'nextcloud-gmbh' }}
 
@@ -22,11 +19,11 @@ jobs:
 
     steps:
       - name: Checkout server
-        uses: actions/checkout@v3
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
         with:
           submodules: true
       - name: Checkout user_saml
-        uses: actions/checkout@v3
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
         with:
           repository: nextcloud/user_saml
           path: apps/user_saml
@@ -42,6 +39,7 @@ jobs:
       - name: Setup AD-DC
         run: |
           DC_IP=$(apps/files_external/tests/sso-setup/start-dc.sh)
+          sleep 1
           apps/files_external/tests/sso-setup/start-apache.sh $DC_IP $PWD
           echo "DC_IP=$DC_IP" >> $GITHUB_ENV
       - name: Set up Nextcloud