Fix YAML syntax error.

Author: khatchad

.github/workflows/continuous-integration.yml

@@ -51,8 +51,8 @@ jobs:
     - name: Build with Maven
       run: mvn -Dlogging.config.file=\${maven.multiModuleProjectDirectory}/logging.ci.properties verify -B
     - name: Deploy with Maven
-        run: mvn -s .travis.settings.xml -Dgithub.username=$GITHUB_USERNAME -Dgithub.password=$GITHUB_TOKEN deploy -DskipTests -B
-        env:
-          GITHUB_USERNAME: ${{ secrets.GITHUB_USERNAME }}
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}
+      run: mvn -s .travis.settings.xml -Dgithub.username=$GITHUB_USERNAME -Dgithub.password=$GITHUB_TOKEN deploy -DskipTests -B
+      env:
+        GITHUB_USERNAME: ${{ secrets.GITHUB_USERNAME }}
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}