Updating gitignore for Thumbs.db

Not specifying any directory means it'll catch all `Thumbs.db` files in any directory.

Author: zautumnz

.gitignore

@@ -4,7 +4,7 @@ latest-change.txt
 patternlab.json
 .sass-cache/*
 /sass-cache
-source/images/Thumbs.db
+Thumbs.db
 source/css/style.css.map
 .idea/
 public