[backport/1.23] ci: Pin images in github actions (#23860)

.github/workflows/check-deps.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     if: github.repository == 'envoyproxy/envoy'
     steps:
       - name: Checkout repository

.github/workflows/codeql-daily.yml

@@ -10,8 +10,8 @@ jobs:
     strategy:
       fail-fast: false
 
-    # CodeQL runs on ubuntu-latest and windows-latest
-    runs-on: ubuntu-latest
+    # CodeQL runs on ubuntu-20.04
+    runs-on: ubuntu-20.04
 
     steps:
     - name: Checkout repository

.github/workflows/codeql-push.yml

@@ -16,8 +16,8 @@ jobs:
     strategy:
       fail-fast: false
 
-    # CodeQL runs on ubuntu-latest and windows-latest
-    runs-on: ubuntu-latest
+    # CodeQL runs on ubuntu-20.04
+    runs-on: ubuntu-20.04
     if: github.repository == 'envoyproxy/envoy'
 
     steps:

.github/workflows/depsreview.yml

@@ -3,7 +3,7 @@ on: [pull_request]
 
 jobs:
   dependency-review:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     if: github.repository == 'envoyproxy/envoy'
     steps:
       - name: 'Checkout Repository'

.github/workflows/pr_notifier.yml

@@ -6,7 +6,7 @@ on:
 jobs:
   pr_notifier:
     name: PR Notifier
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     if: github.repository == 'envoyproxy/envoy'
     steps:
     - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b

.github/workflows/stale.yml

@@ -9,7 +9,7 @@ jobs:
       issues: write  # for actions/stale to close stale issues
       pull-requests: write  # for actions/stale to close stale PRs
     name: Prune Stale
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     if: github.repository == 'envoyproxy/envoy'
 
     steps: