chore: update mysql example

Author: appleboy

1.x/docker-compose.github.mysql.yml

@@ -17,18 +17,21 @@ services:
       - DRONE_GITHUB_SERVER=https://github.com
       - DRONE_GITHUB_CLIENT_ID=${DRONE_GITHUB_CLIENT_ID}
       - DRONE_GITHUB_CLIENT_SECRET=${DRONE_GITHUB_CLIENT_SECRET}
+
       - DRONE_LOGS_PRETTY=true
       - DRONE_LOGS_COLOR=true
 
-  drone-agent:
-    image: drone/agent:1
+  # runner for docker version
+  drone-runner:
+    image: drone/drone-runner-docker:1
     restart: always
     depends_on:
       - drone-server
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
     environment:
-      - DRONE_RPC_SERVER=http://drone-server
+      - DRONE_RPC_HOST=${DRONE_RPC_HOST}
+      - DRONE_RPC_PROTO=${DRONE_RPC_PROTO}
       - DRONE_RPC_SECRET=${DRONE_RPC_SECRET}
       - DRONE_RUNNER_CAPACITY=3