Add type definitions

packages/content-handler/package.json

@@ -16,6 +16,7 @@
   },
   "devDependencies": {
     "@types/addressparser": "^1.0.1",
+    "@types/lodash": "^4.14.194",
     "@types/luxon": "^3.0.1",
     "@types/rfc2047": "^2.0.1",
     "@types/underscore": "^1.11.4",

yarn.lock

@@ -8458,6 +8458,11 @@
   resolved "https://registry.yarnpkg.com/@types/lodash/-/lodash-4.14.180.tgz#4ab7c9ddfc92ec4a887886483bc14c79fb380670"
   integrity sha512-XOKXa1KIxtNXgASAnwj7cnttJxS4fksBRywK/9LzRV5YxrF80BXZIGeQSuoESQ/VkUj30Ae0+YcuHc15wJCB2g==
 
+"@types/lodash@^4.14.194":
+  version "4.14.194"
+  resolved "https://registry.yarnpkg.com/@types/lodash/-/lodash-4.14.194.tgz#b71eb6f7a0ff11bff59fc987134a093029258a76"
+  integrity sha512-r22s9tAS7imvBt2lyHC9B8AGwWnXaYb1tY09oyLkXDs4vArpYJzw09nj8MLx5VfciBPGIb+ZwG0ssYnEPJxn/g==
+
 "@types/long@^4.0.0", "@types/long@^4.0.1":
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/@types/long/-/long-4.0.2.tgz#b74129719fc8d11c01868010082d483b7545591a"