chore: lock rc-dropdown (#494)

Author: MadCcc

package.json

@@ -76,7 +76,7 @@
   "dependencies": {
     "@babel/runtime": "^7.11.2",
     "classnames": "2.x",
-    "rc-dropdown": "^3.2.0",
+    "rc-dropdown": "~3.3.0",
     "rc-menu": "~9.5.1",
     "rc-resize-observer": "^1.0.0",
     "rc-util": "^5.5.0"