Update codemirror to 5.46.2

Signed-off-by: Yukai Huang <yukaihuangtw@gmail.com>

Author: Yukaii

package.json

@@ -26,7 +26,7 @@
     "test": "npm run-script eslint && npm run-script jsonlint && mocha"
   },
   "dependencies": {
-    "@hackmd/codemirror": "~5.41.2",
+    "@hackmd/codemirror": "^5.46.2",
     "@hackmd/diff-match-patch": "~1.1.1",
     "@hackmd/idle-js": "~1.0.1",
     "@hackmd/imgur": "~0.4.1",