Add options to skip caching of folders. (#154)

Add option to skip caching the Go package directory (~/go/pkg).
Add option to skip caching the Go build directory (~/.cache/go-build).
Update README to mention new options.

action.yml

@@ -24,6 +24,14 @@ inputs:
     description: "if set to true then action uses pre-installed Go"
     default: false
     required: true
+  skip-pkg-cache:
+    description: "if set to true then the action don't cache or restore ~/go/pkg."
+    default: false
+    required: true
+  skip-build-cache:
+    description: "if set to true then the action don't cache or restore ~/.cache/go-build."
+    default: false
+    required: true
 runs:
   using: "node12"
   main: "dist/run/index.js"