Rename update release assets script

We replace `-` with `_` so we can you use the default import statement
to import the script as a module.

Author: rvermeulen

.github/workflows/update-release.yml

@@ -54,7 +54,7 @@ jobs:
           GITHUB_TOKEN: ${{ github.token }}
           RELEASE_ENGINEERING_TOKEN: ${{ steps.generate-token.outputs.token }}
         run: |
-          python scripts/release/update-release-assets.py \
+          python scripts/release/update_release_assets.py \
             --head-sha $HEAD_SHA \
             --layout scripts/release/release-layout.yml \
             --repo "$GITHUB_REPOSITORY" \