Checkout source code in release to be able to use script

Signed-off-by: Ryan Levick <ryan.levick@fermyon.com>

Author: rylev

.github/workflows/release.yaml

@@ -194,6 +194,9 @@ jobs:
     needs: release
     steps:
 
+      - name: checkout source
+        uses: actions/checkout@v3
+
       - name: set the release version (tag)
         if: startsWith(github.ref, 'refs/tags/v')
         shell: bash