CI: Pin database versions

Signed-off-by: Stephen Finucane <stephen@that.guru>

Author: stephenfin

.github/workflows/ci.yaml

@@ -47,7 +47,7 @@ jobs:
       MYSQL_ROOT_PASSWORD: root-${{ github.run_id }}
     services:
       postgres:
-        image: postgres:latest
+        image: postgres:17
         env:
           POSTGRES_DB: ${{ env.DATABASE_NAME }}
           POSTGRES_PASSWORD: ${{ env.DATABASE_PASSWORD }}
@@ -60,7 +60,7 @@ jobs:
           --health-timeout 5s
           --health-retries 5
       mysql:
-        image: mysql:latest
+        image: mysql:8.4
         env:
           MYSQL_DATABASE: ${{ env.DATABASE_NAME }}
           MYSQL_USER: ${{ env.DATABASE_USER }}