Update other packages to use http-client v2 (#1082)

We moved `@actions/http-client` to be part of the toolkit in https://github.com/actions/toolkit/pull/1062.  We also made some breaking changes to exported types and released v2.

The biggest change in terms of lines of code affected was to get rid of the `I-` prefix for interfaces since TypeScript doesn't follow this convention.

I bumped the patch version of all packages except for `tool-cache`, where I bumped the major version.  The rationale is explained in the release notes for that package.

packages/core/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@actions/core",
-  "version": "1.8.0",
+  "version": "1.8.1",
   "description": "Actions core lib",
   "keywords": [
     "github",
@@ -36,7 +36,7 @@
     "url": "https://github.com/actions/toolkit/issues"
   },
   "dependencies": {
-    "@actions/http-client": "^1.0.11"
+    "@actions/http-client": "^2.0.0"
   },
   "devDependencies": {
     "@types/node": "^12.0.2"