fix: GPG key and Maven credentials in release workflow (#171)

Revised the GPG key and Maven credentials used in the GitHub release
workflow for better security and consistency. The `gpg-private-key` and
`gpg-passphrase` are now using updated secret variables. Updated the
Maven credentials to use consistent naming conventions across the
workflow.

.github/workflows/release.yaml

@@ -41,14 +41,14 @@ jobs:
           server-id: github
           server-username: MAVEN_USERNAME
           server-password: MAVEN_PASSWORD
-          gpg-private-key: ${{ secrets.OPENTDF_GPG_KEY }}
-          gpg-passphrase: ${{ secrets.OPENTDF_GPG_KEY_PASSPHRASE }}
+          gpg-private-key: ${{ secrets.GPG_KEY }}
+          gpg-passphrase: MAVEN_GPG_PASSPHRASE
       - name: Publish package
         run: mvn --batch-mode deploy -DskipTests
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           BUF_INPUT_HTTPS_USERNAME: opentdf-bot
           BUF_INPUT_HTTPS_PASSWORD: ${{ secrets.PERSONAL_ACCESS_TOKEN_OPENTDF }}
-          MAVEN_USERNAME: ${{ secrets.MAVEN_CENTRAL_USERNAME }}
-          MAVEN_PASSWORD: ${{ secrets.MAVEN_CENTRAL_PASSWORD }}
-          MAVEN_GPG_PASSPHRASE: ${{ secrets.OPENTDF_GPG_KEY_PASSPHRASE }}
+          MAVEN_USERNAME: ${{ secrets.MAVEN_USERNAME }}
+          MAVEN_PASSWORD: ${{ secrets.MAVEN_PASSWORD }}
+          MAVEN_GPG_PASSPHRASE: ${{ secrets.GPG_KEY_PASSPHRASE }}