Fix bad env usage in gha workflows

Author: sayhiben

.github/workflows/deploy.yml

@@ -23,7 +23,7 @@ jobs:
 
     services:
       postgres:
-        image: postgres:${{ env.POSTGRES_VERSION }}
+        image: postgres:18
         env:
           POSTGRES_PASSWORD: postgres
           POSTGRES_DB: streamsource_test
@@ -36,7 +36,7 @@ jobs:
           - 5432:5432
 
       redis:
-        image: redis:${{ env.REDIS_VERSION }}
+        image: redis:8
         options: >-
           --health-cmd "redis-cli ping"
           --health-interval 10s

.github/workflows/pr-validation.yml

@@ -25,7 +25,7 @@ jobs:
 
     services:
       postgres:
-        image: postgres:${{ env.POSTGRES_VERSION }}
+        image: postgres:18
         env:
           POSTGRES_PASSWORD: postgres
           POSTGRES_DB: streamsource_test
@@ -38,7 +38,7 @@ jobs:
           - 5432:5432
 
       redis:
-        image: redis:${{ env.REDIS_VERSION }}
+        image: redis:8
         options: >-
           --health-cmd "redis-cli ping"
           --health-interval 10s