templates: automatically apply patches with %autopatch
    
    It's recommended to use %autosetup to setup the build directory and
    automatically apply patches. For Go packages, %goprep is used instead of
    %autosetup. %goprep calls %setup under the hood like %autosetup does,
    but it doesn't apply patches. Let's add %autopatch to preform the second
    part so Go packagers don't resort to manual %patch calls. Hopefully,
    this will also prevent people from accidentally using deprecated %patchN
    syntax[1].
    
    [1] https://github.com/rpm-software-management/rpm/blob/master/docs/manual/spec.md#patch-1