Merge pull request #634 from go-debos/copilot/add-github-actions-usage-docs

docs: Add GitHub Actions usage documentation to README

Author: obbardc

README.md

@@ -83,6 +83,24 @@ docker pull godebos/debos
 
 See [docker/README.md](docker/README.md) for usage.
 
+## Using debos in GitHub Actions
+
+debos can be run in GitHub Actions using the official container with KVM support
+for isolated and reproducible builds. The `--fakemachine-backend=kvm` option is
+specified to ensure KVM is used as expected:
+
+```yaml
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/go-debos/debos:main
+      options: --device=/dev/kvm
+    steps: 
+      - uses: actions/checkout@v4
+      - run: debos --fakemachine-backend=kvm --print-recipe recipe.yaml
+```
+
 ## Installation from source (under Debian)
 
 ```bash