Add configured signatory [skip ci]

Author: nakamura-to

.github/workflows/ci.yml

@@ -94,6 +94,11 @@ jobs:
       - name: Build with Gradle (doma)
         working-directory: ./doma
         run: ./gradlew build -x check
+        env:
+          ORG_GRADLE_PROJECT_signingKey: ${{ secrets.SIGNING_KEY }}
+          ORG_GRADLE_PROJECT_signingPassword: ${{ secrets.SIGNING_PASSWORD }}
+          ORG_GRADLE_PROJECT_sonatypeUsername: ${{ secrets.OSSRH_USERNAME }}
+          ORG_GRADLE_PROJECT_sonatypePassword: ${{ secrets.OSSRH_PASSWORD }}
 
       - name: Checkout (doma-it)
         uses: actions/checkout@v2