lang/gcc11: Deprecate with an expiration date of 2025-07-19

GCC 11 went end of life with the relase of GCC 11.5 on 2024-07-19,
so time to deprecate and expire one year afterwards.

With GCC 12, GCC 13, and GCC 14 there are three robust release
branches available, and even GCC 15.1 has been released now.

PR: 266189
Approved by: maintainer