chore: ignoreでサンプルアプリのpubspecの追跡中止

Author: LibraryLibrarian

.gitignore

@@ -151,7 +151,7 @@ http-client.private.env.json
 .packages
 build/
 ## If you're building an application, you may want to check-in your pubspec.lock
-pubspec.lock
+/pubspec.lock
 
 ## Directory created by dartdoc
 # If you don't generate documentation locally you can remove this line.