Run on Ubuntu 20.04 while using docker-compose

.github/workflows/ci.yaml

@@ -8,7 +8,7 @@ name: CI
 jobs:
   build:
     name: Build server image
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     services:
       postgres:
         image: postgres:15
@@ -54,7 +54,7 @@ jobs:
 
   buildwww:
     name: Build httpd+cgi image
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
     - name: Checkout
       uses: actions/checkout@v4
@@ -73,7 +73,7 @@ jobs:
 
   buildclient:
     name: Build client image
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
     - name: Checkout
       uses: actions/checkout@v4
@@ -93,7 +93,7 @@ jobs:
   test-scripts:
     name: Run test scripts
     needs: [build, buildwww, buildclient]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         test:
@@ -143,7 +143,7 @@ jobs:
     if: ${{ github.ref == 'refs/heads/master' || startsWith(github.ref, 'refs/tags/') }}
     name: Publish server image
     needs: [test-scripts]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     permissions:
       packages: write
       contents: read
@@ -173,7 +173,7 @@ jobs:
     if: ${{ github.ref == 'refs/heads/master' || startsWith(github.ref, 'refs/tags/') }}
     name: Publish httpd+cgi image
     needs: [test-scripts]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     permissions:
       packages: write
       contents: read
@@ -202,7 +202,7 @@ jobs:
 #  cd_hook:
 #    name: Webhook to local builders
 #    needs: [test-scripts]
-#    runs-on: ubuntu-latest
+#    runs-on: ubuntu-20.04
 #    continue-on-error: true
 #    steps:
 #      - name: HTTP request
@@ -212,7 +212,7 @@ jobs:
     if: ${{ github.ref == 'refs/heads/master' }}
     name: Tag and release
     needs: [test-scripts]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v4
         with: