build: add .DS_store to .gitgnore

The following files were not being ignored:

deps/npm/node_modules/node-gyp/gyp/tools/.DS_Store
deps/npm/node_modules/node-gyp/gyp/tools/Xcode/.DS_Store

PR-URL: #23554
Reviewed-By: Hitesh Kanwathirtha <digitalinfinity@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

.gitignore

@@ -133,3 +133,5 @@ deps/uv/docs/src/guide/
 deps/v8/gypfiles/Debug/
 deps/v8/gypfiles/Release/
 deps/v8/third_party/eu-strip/
+
+.DS_Store