gpu-dawn: checkout repo so we can use git rev-parse

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

gpu-dawn/.github/workflows/draft_release.yml

@@ -7,6 +7,8 @@ jobs:
   draft:
     runs-on: ubuntu-latest
     steps:
+    - name: Checkout
+      uses: actions/checkout@v2
     - name: Create draft
       run: gh release create $(git rev-parse --short HEAD) --title "Automatic release of main @ $(git rev-parse --short HEAD)"
       env: