build(package): simplify repository fields

created using @octoherd and https://github.com/gr2m/octoherd-script-normalize-package-repository-field

Author: gr2m

package.json

@@ -11,7 +11,7 @@
   "dependencies": {
     "@probot/adapter-aws-lambda-serverless": "^2.0.0"
   },
-  "repository": "https://github.com/probot/example-aws-lambda-serverless",
+  "repository": "github:probot/example-aws-lambda-serverless",
   "keywords": [],
   "author": "Gregor Martynus (https://twitter.com/gr2m)",
   "license": "ISC",