ci: harden GitHub Actions snapshot workflow by using SHA hash for dependency (#122)

Thanks to https://app.stepsecurity.io/secure-repo

Reviewed-by: Pierre-Yves Lapersonne <[email protected]>
Signed-off-by: StepSecurity Bot <[email protected]>
Signed-off-by: Pierre-Yves Lapersonne <[email protected]>

Author: step-security-bot

.github/workflows/snapshot.yml

@@ -32,7 +32,7 @@ jobs:
   snapshot:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4.3.0
         with:
           ref: develop
           token: ${{ secrets.GITHUB_TOKEN }}