ci: Update codgen workflow commit message

Signed-off-by: Dave Tucker <dave@dtucker.co.uk>

.github/workflows/gen.yml

@@ -35,7 +35,7 @@ jobs:
         with:
           github_token: "${{ secrets.GITHUB_TOKEN }}"
           commit_prefix: "[codegen] Update libbpf to ${{ env.LIBBPF_SHA }}"
-          commit_message: "Created using GitHub Actions"
+          commit_message: "Update libbpf to ${{ env.LIBBPF_SHA }}"
           target_branch: codegen