add ver

.drone.yml

   - echo "remove files in ${DRONE_REPO_NAME}"; rm -rf ./*
   - echo "copy docs to ${DRONE_REPO_NAME}"; cp -r ../docs/* .
   - ls
+  - echo "# Version" >> ./README.md
+  - echo "${DRONE_TAG}" >> ./README.md
   - echo "add files in ${DRONE_REPO_NAME}"; git add -A
   - git commit --allow-empty -m "Drone tagged as ${DRONE_TAG}"
   - git push --force origin master