fix typescript dependency error

package.json

@@ -80,7 +80,7 @@
     "showdown": "^1.9.1",
     "ts-loader": "^4.3.0",
     "ts-node": "^8.1.0",
-    "typescript": "^3.7.5",
+    "typescript": "~3.7.5",
     "uglifyjs-webpack-plugin": "^1.2.5",
     "webpack": "^4.41.2",
     "webpack-cli": "^3.3.2",