Remove gpg steps for PR from fork

Author: minosiants

.github/workflows/pr_scala_3.yml

@@ -28,11 +28,13 @@ jobs:
         run: sbt test
 
       - name: Import GPG key
+        if: github.event.pull_request.head.repo.fork == false
         id: import_gpg
         uses: crazy-max/ghaction-import-gpg@v3
         with:
           gpg-private-key: ${{ secrets.GPG_PRIVATE_KEY }}
           passphrase: ${{ secrets.PGP_PASSPHRASE }}
 
       - name: publish local
+        if: ${{ secrets.GPG_PRIVATE_KEY != '' }}
         run: sbt publishLocalSigned