dev: improve description

README.md

@@ -2,9 +2,10 @@
 
 [![Build Status](https://github.com/golangci/golangci-lint-action/workflows/build-and-test/badge.svg)](https://github.com/golangci/golangci-lint-action/actions)
 
-![GitHub Annotations](./static/annotations.png)
+It's the official GitHub action for [golangci-lint](https://github.com/golangci/golangci-lint) from it's authors.
+The action runs [golangci-lint](https://github.com/golangci/golangci-lint) and reports issues from linters.
 
-The action that runs [golangci-lint](https://github.com/golangci/golangci-lint) and reports issues from linters.
+![GitHub Annotations](./static/annotations.png)
 
 ## How to use
 
@@ -57,6 +58,13 @@ The action was implemented with performance in mind:
 2. We don't use Docker because image pulling is slow.
 3. We do as much as we can in parallel, e.g. we download cache, go and golangci-lint binary in parallel.
 
+For example, in a repository of [golangci-lint](https://github.com/golangci/golangci-lint) running this action without the cache takes 50s, but with cache takes 14s:
+  * in parallel:
+    * 13s to download Go
+    * 4s to restore 50 MB of cache
+    * 1s to find and install `golangci-lint`
+  * 1s to run `golangci-lint` (it takes 35s without cache)
+
 ## Internals
 
 We use JavaScript-based action. We don't use Docker-based action because:

action.yml

@@ -1,6 +1,6 @@
 ---
 name: 'Run golangci-lint'
-description: 'Run golangci-lint (WIP)'
+description: 'Official golangci-lint runner. Works very fast: uses caching and parallelization. Creates line-attached GitHub annotations for found issues. Beta version.'
 author: 'golangci'
 inputs:
   version:
@@ -19,5 +19,5 @@ runs:
   main: 'dist/run/index.js'
   post: 'dist/post_run/index.js'
 branding:
-  icon: 'check-circle'
+  icon: 'shield'
-  color: 'blue'
+  color: 'yellow'