docc validation needs JAVA_HOME to be set up

Author: ktoso

.github/workflows/pull_request.yml

@@ -5,7 +5,11 @@ on:
     types: [opened, reopened, synchronize]
 
 jobs:
+  env-setup:
+    uses: ./.github/actions/prepare_env/action.yml
+
   soundness:
+    needs: env-setup
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
     with:
       # Not API stable package (yet)