Add support for a YAML config file

package.json

@@ -33,6 +33,7 @@
     "@types/adm-zip": "^0.4.32",
     "@types/fs-extra": "^8.0.1",
     "@types/http-proxy": "^1.17.4",
+    "@types/js-yaml": "^3.12.3",
     "@types/mocha": "^5.2.7",
     "@types/node": "^12.12.7",
     "@types/parcel-bundler": "^1.12.1",
@@ -69,13 +70,15 @@
     "fs-extra": "^8.1.0",
     "http-proxy": "^1.18.0",
     "httpolyglot": "^0.1.2",
+    "js-yaml": "^3.13.1",
     "limiter": "^1.1.5",
     "pem": "^1.14.2",
     "safe-compare": "^1.1.4",
     "semver": "^7.1.3",
     "tar": "^6.0.1",
     "tar-fs": "^2.0.0",
-    "ws": "^7.2.0"
+    "ws": "^7.2.0",
+    "xdg-basedir": "^4.0.0"
   },
   "bin": {
     "code-server": "out/node/entry.js"