GitBook: [#206] deep update example

usage/github-action.md

@@ -0,0 +1,29 @@
+# GitHub Action
+
+You can use `yq` in your GitHub action, for instance:
+
+```yaml
+  - uses: actions/checkout@v2
+  - name: Get SDK Version from config
+    id: lookupSdkVersion
+    uses: mikefarah/yq@master
+    with:
+      cmd: yq eval '.renutil.version' 'config.yml'
+  - name: Restore Cache
+    id: restore-cache
+    uses: actions/cache@v2
+    with:
+      path: ../renpy
+      key:  ${{ runner.os }}-sdk-${{ steps.lookupSdkVersion.outputs.result }}
+      restore-keys: |
+        ${{ runner.os }}-sdk
+  # ... more
+```
+
+The `yq` action sets a `result` variable in its output, making it available to subsequent steps. In this case it's available as `steps.lookupSdkVersion.outputs.result`.
+
+Details of how the GitHub action itself is configured can be found [here](https://github.com/mikefarah/yq/issues/844#issuecomment-856700574)
+
+If you [enable step debug logging](https://docs.github.com/en/actions/managing-workflow-runs/enabling-debug-logging#enabling-step-debug-logging), you can see additional information about the exact command sent as well as the response returned within the GitHub Action logs.
+
+Thanks @[**devorbitus**](https://github.com/devorbitus)**!**