update drone.yml

drone.yml

     - cp -rp html/. dist/var/www/html/gamma/
     - mkdir -p dist/etc/nginx/snippets
     - cp -p config/nginx-datasrc-location.conf dist/etc/nginx/snippets/nginx-datasrc-location.conf
-    - RELEASE=${REPO_NAME}-${BRANCH}
+    - RELEASE=${DRONE_REPO_NAME}-$DRONE_BRANCH
     - mv dist $RELEASE
     - ls -la $RELEASE
     - find $RELEASE -type f -exec md5sum '{}' \;