Update workflow version

Author: chrispenny

.github/workflows/main.yaml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   ci:
-    uses: silverstripe/gha-ci/.github/workflows/ci.yml@v1
+    uses: silverstripe/gha-ci/.github/workflows/ci.yml@v2
     with:
       # disable auto detection of JS tests (remove if any JS tests are added)
       js: false