proxy support (#166)

* Replace typed rest client with new http-client

* Send Content-Type: application/json and fix up some types

* Lint

* Consume @actions/http-client:1.0.5

* Consume @actions/http-client:1.0.6

* Dont send headers manually, http-client automatically will

.gitignore

@@ -94,3 +94,6 @@ typings/
 
 # DynamoDB Local files
 .dynamodb/
+
+# Text editor files
+.vscode/