Manage old issues/pull requests

[t2y]

I found some pull requests that are left for more than one year. Also, some issues may not make sense.

To reduce the maintainer's cost, how about closing them with a specific label if the maintainer won't support/be interested in them? For example, golang/go has FrozenDueToAge.

• https://github.com/golang/go/issues?q=label%3AFrozenDueToAge+
• https://github.com/golang/go/pulls?q=label%3AFrozenDueToAge+