Try adding gpg stuff

Author: purejava

.github/workflows/release_to_maven.yml

@@ -63,5 +63,7 @@ jobs:
       - name: Publish package
         run: ./gradlew publishToSonatype closeSonatypeStagingRepository
         env:
+          GPG_SIGNING_KEY: ${{ secrets.GPG_PRIVATE_KEY }}
+          GPG_SIGNING_PASSPHRASE: ${{ secrets.GPG_PASSPHRASE }}
           SONATYPE_USERNAME: ${{ secrets.NEXUS_USERNAME }}
           SONATYPE_PASSWORD: ${{ secrets.NEXUS_PASSWORD }}