fix: changed ubuntu version to 20.04

Author: akshat5302

.github/workflows/chart-preview.yml

@@ -31,7 +31,7 @@ env:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: Checkout Source
         uses: actions/checkout@v4