ubuntu version (#37948)

diff --git a/.github/workflows/scorecards-analysis.yml b/.github/workflows/scorecards-analysis.yml
index 03682a7..5bdab6c 100644
--- a/.github/workflows/scorecards-analysis.yml
+++ b/.github/workflows/scorecards-analysis.yml
@@ -11,7 +11,7 @@
 jobs:
   vuln-scan:
     name: Vulnerability scanning
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     if: ${{ github.repository == 'flutter/engine' }}
     steps:
       - name: "Checkout code"