Readd .gitignore after deleting it.

pkgs/package_config/.gitignore

diff --git a/pkgs/package_config/.gitignore b/pkgs/package_config/.gitignore
new file mode 100644
index 0000000..7b888b8
--- /dev/null
+++ b/pkgs/package_config/.gitignore
@@ -0,0 +1,7 @@
+.packages
+.pub
+.dart_tool/
+.vscode/
+packages
+pubspec.lock
+doc/api/