Docs/process/changes: Replace http:// with https://

Some links are still using 'http://'.  Replace those with 'https://'.

Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230728211616.59550-2-sj@kernel.org