fix: add yarn gitignores to template

AndersDJohnson · AndersDJohnson · commit a510d5a4050c · 2017-02-09T00:09:57.000-06:00
diff --git a/packages/react-scripts/template/gitignore b/packages/react-scripts/template/gitignore
@@ -13,3 +13,6 @@
 .DS_Store
 .env
 npm-debug.log
+yarn-debug.log*
+yarn-error.log*
+
