build: add node-fetch typings

Author: hansl

package.json

@@ -63,6 +63,7 @@
     ]
   },
   "dependencies": {
+    "@types/node-fetch": "^2.1.6",
     "@types/progress": "^2.0.3",
     "glob": "^7.0.3",
     "node-fetch": "^2.2.0",

yarn.lock

@@ -394,6 +394,13 @@
   resolved "https://registry.yarnpkg.com/@types/minimist/-/minimist-1.2.0.tgz#69a23a3ad29caf0097f06eda59b361ee2f0639f6"
   integrity sha1-aaI6OtKcrwCX8G7aWbNh7i8GOfY=
 
+"@types/node-fetch@^2.1.6":
+  version "2.1.6"
+  resolved "https://registry.yarnpkg.com/@types/node-fetch/-/node-fetch-2.1.6.tgz#4326288b49f352a142f03c63526ebce0f4c50877"
+  integrity sha512-Hv1jgh3pfpUEl2F2mqUd1AfLSk1YbUCeBJFaP36t7esAO617dErqdxWb5cdG2NfJGOofkmBW36fdx0dVewxDRg==
+  dependencies:
+    "@types/node" "*"
+
 "@types/node@*":
   version "10.9.4"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-10.9.4.tgz#0f4cb2dc7c1de6096055357f70179043c33e9897"