chore: move pg string to env

.github/workflows/infra-build.yml

@@ -11,6 +11,9 @@ jobs:
     runs-on: self-hosted
     container:
       image: node:20-bullseye
+    
+    env:
+      PG_CONN_STR: ${{ secrets.PG_CONN_STR }}   # available to all steps
      
     steps:
       - name: Checkout code
@@ -45,7 +48,6 @@ jobs:
       - name: Opentofu Plan
         id: plan
         run: |
-          export PG_CONN_STR="${{ secrets.PG_CONN_STR }}"
           tofu plan -out=tfplan -detailed-exitcode
 
       - name: Opentofu Apply