Retry all http calls for artifact upload and download (#675)

* Retry all http calls for artifact upload and download

* Extra debug information

* Fix lint

* Always read response body

* PR Feedback

* Change error message if patch call fails

* Add exponential backoff when retrying

* Rework tests and add diagnostic info if exception thrown

* Fix lint

* fix lint error for real this time

* PR cleanup

* 0.5.0 @actions/artifact release

* Display diagnostic info if non-retryable code is hit

packages/artifact/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@actions/artifact",
-  "version": "0.4.2",
+  "version": "0.5.0",
   "preview": true,
   "description": "Actions artifact lib",
   "keywords": [