Fixes #24 Unable to Upload to the Central Repository

* Change build script to write all secrets to gradle.properties

.github/workflows/publish-library.yml

@@ -18,21 +18,19 @@ jobs:
         distribution: 'temurin'
         cache: gradle
 
-    - name: Write Out GPG Key
+    - name: Write Out Secrets to Gradle
       run: |
+        echo centralUsername=$CENTRAL_REPOSITORY_USERNAME >> gradle.properties
+        echo centralPassword=$CENTRAL_REPOSITORY_PASSWORD >> gradle.properties
         echo GPG_SIGNING_KEY=$GPG_SIGNING_KEY >> gradle.properties
         echo GPG_SIGNING_KEY_PASSWORD=$GPG_SIGNING_KEY_PASSWORD >> gradle.properties
       env:
+        CENTRAL_REPOSITORY_USERNAME: ${{ secrets.CENTRAL_REPOSITORY_USERNAME }}
+        CENTRAL_REPOSITORY_PASSWORD: ${{ secrets.CENTRAL_REPOSITORY_PASSWORD }}
         GPG_SIGNING_KEY: ${{ secrets.GPG_SIGNING_KEY }}
         GPG_SIGNING_KEY_PASSWORD: ${{ secrets.GPG_SIGNING_KEY_PASSWORD }}
 
     - name: Publish the Library
       uses: gradle/gradle-build-action@v2
       with:
-        arguments: |
-          publishMultimodalSpannerPublicationToCentralRepository
-          -PcentralUsername=$CENTRAL_REPOSITORY_USERNAME
-          -PcentralPassword=$CENTRAL_REPOSITORY_PASSWORD
-      env:
-        CENTRAL_REPOSITORY_USERNAME: ${{ secrets.CENTRAL_REPOSITORY_USERNAME }}
-        CENTRAL_REPOSITORY_PASSWORD: ${{ secrets.CENTRAL_REPOSITORY_PASSWORD }}
+        arguments: publishMultimodalSpannerPublicationToCentralRepository