ci: Fix release workflow (#154)

Remove optional property (gpg key id)

Author: petertrr

.github/workflows/release.yml

@@ -4,10 +4,11 @@ on:
  push:
  tags:
  - 'v*'
+ # TODO: only for testing
+ pull_request:
 
 env:
  # See https://vanniktech.github.io/gradle-maven-publish-plugin/central for the list of required properties
- ORG_GRADLE_PROJECT_signingInMemoryKeyId: ${{ vars.PGP_KEY_ID }}
  ORG_GRADLE_PROJECT_signingInMemoryKey: ${{ secrets.PGP_SEC }}
  ORG_GRADLE_PROJECT_signingInMemoryKeyPassword: ${{ secrets.PGP_PASSWORD }}
  ORG_GRADLE_PROJECT_mavenCentralUsername: ${{ secrets.CENTRAL_PORTAL_USER }}