added suppression for certificateRefresher_test.go

.config/CredScanSuppressions.json

@@ -1,6 +1,10 @@
 {
     "tool": "Credential Scanner",
     "suppressions": [
+        {
+            "file": "pkg/env/certificateRefresher_test.go",
+            "_justification": "sample cert for testing"
+        },
         {
             "file": "proxy_test.go",
             "_justification": "sample login for testing"