workflows: run CD on Ubuntu 20.04

So we can get newer git-buildpackage

.github/workflows/cd.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   cd:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: Checkout code
         uses: actions/checkout@v2

pkg/utils/utils.go

@@ -102,8 +102,8 @@ func Loader() string {
 // ResolvePlaceholderString populates a template with values
 func ResolvePlaceholderString(str string, arguments map[string]string) string {
 	for key, value := range arguments {
-		str = strings.ReplaceAll(str, "{{"+key+"}}", value)
-		str = strings.ReplaceAll(str, "{{."+key+"}}", value)
+		str = strings.Replace(str, "{{"+key+"}}", value, -1)
+		str = strings.Replace(str, "{{."+key+"}}", value, -1)
 	}
 	return str
 }