Update dependency prometheus-client-mmap to '~> 1.1', '>= 1.1.1'

What does this MR do and why?

This backports !143159 (merged) to solve high committed RAM usage identified in omnibus-gitlab#8373 (closed).

This reverts gitlab-org/ruby/gems/prometheus-client-mmap!137 (merged).

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• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
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