pw_thread_stl: Add missing header include
pw_thread_stl: Add missing header include

This commit adds the missing '#include <algorithm>', required to use
std::max. This is necessary when compiling with GCC 12, presumably
because another header stopped transitively including 'algorithm'.

Change-Id: I3ebc2694f050daab8ee72e1ad6279bf775d15e19
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/112863
Commit-Queue: Eli Lipsitz <5e22d96bbb1fbd3e8d6957aa196f0ee1be483ecf@google.com>
Reviewed-by: Chad Norvell <f2b1b54074a2cea3f685a7cf4fc055999c2f0cd6@google.com>
Pigweed-Auto-Submit: Eli Lipsitz <5e22d96bbb1fbd3e8d6957aa196f0ee1be483ecf@google.com>

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