Add pgp env variables in publishing workflow

Author: michallaskowski

.github/workflows/publishing-workflow.yml

@@ -38,4 +38,6 @@ jobs:
         env:
           MAVEN_USERNAME: ${{ secrets.MAVEN_USERNAME }}
           MAVEN_PASSWORD: ${{ secrets.MAVEN_PASSWORD }}
+          PGP_SIGNING_KEY: ${{ secrets.PGP_SIGNING_KEY }}
+          PGP_SIGNING_PASSWORD: ${{ secrets.PGP_SIGNING_PASSWORD }}
         run: ./gradlew library:publish