add checkout action.yml (#1)

* initial test.

* test

* Update action.yml

* Update action.yml

* Update action.yml

* Update action.yml

* Update action.yml

Author: TingluoHuang

action.yml

@@ -0,0 +1,22 @@
+name: 'Checkout'
+description: 'Get sources from a GitHub repository.'
+inputs: 
+  repository:
+    description: 'Repository name'
+  ref:
+    description: 'Ref to checkout (SHA, branch, tag)'
+  token:
+    description: 'Access token for clone repository'
+  clean:
+    description: 'If true, execute `execute git clean -ffdx && git reset --hard HEAD` before fetching'
+    default: true
+  submodules:
+    description: 'Directory containing files to upload'
+  lfs:
+    description: 'Whether to download Git-LFS files; defaults to false'
+  fetch-depth:
+    description: 'The depth of commits to ask Git to fetch; defaults to no limit'  
+  path:
+    description: 'Optional path to check out source code'  
+runs:
+  plugin: 'checkout'