Enable cvc5's CI

Author: filipeom

.github/workflows/test-cvc5.yml

@@ -2,12 +2,12 @@ name: Test cvc5
 
 on:
   pull_request:
-    types: [ labeled ]
+    branches:
+      - main
   workflow_dispatch:
 
 jobs:
   test-cvc5:
-    if: github.event.label.name == 'cvc5'
     runs-on: ubuntu-latest
     env:
       OPAMJOBS: 4