Introduce PathSpec for StatusOptions.
Introduce StatusOptions.DisablePathSpecMatch
Update libgit2 to 19ae843

https://github.com/libgit2/libgit2/compare/3f8d005a82b39c504220d65b6a6aa696c3b1a9c4...19ae843937bed26ddf522a4eb00953c81b1a4561