Fix atscfg strings.ReplaceAll to Replace (#4176)

The strings.ReplaceAll func doesn't exist in our current pinned
version of Go, 1.11.
diff --git a/lib/go-atscfg/parentdotconfig_test.go b/lib/go-atscfg/parentdotconfig_test.go
index b52345d..cdda47c 100644
--- a/lib/go-atscfg/parentdotconfig_test.go
+++ b/lib/go-atscfg/parentdotconfig_test.go
@@ -318,7 +318,7 @@
 
 	testComment(t, txt, serverName, toolName, toURL)
 
-	txt = strings.ReplaceAll(txt, " ", "")
+	txt = strings.Replace(txt, " ", "", -1)
 
 	if !strings.Contains(txt, `secondary_parent="my-parent-1.my-parent-1-domain`) {
 		t.Errorf("expected secondary parent 'my-parent-1.my-parent-1-domain', actual: '%v'", txt)