ruby: update to 2.7.1

ruby: update to 2.7.1

New subpackages (reflect of ongoing ruby gemification)
- ruby-benchmark (from ruby-debuglib)
- ruby-delegate (from ruby-misc)
- ruby-getoptlong (from ruby-misc)
- ruby-net-pop (from ruby-net)
- ruby-net-imap (from ruby-net)
- ruby-observer (from ruby-patterns, now gone)
- ruby-open3 (from ruby-misc)
- ruby-readline-ext (was ruby-readline, while ruby-readline now selects either
    ruby-readline-ext or ruby-reline)
- ruby-reline (alternative to ruby-readline-ext as pure ruby)
- ruby-singleton (from ruby-patterns, now gone)
- ruby-timeout (from ruby-multithread)

Dropped subpackages:
- ruby-cmath (gone in 2.7.0)
- ruby-e2mmap (gone in 2.7.0)
- ruby-patterns (splitted into ruby-observer, ruby-singleton)
- ruby-scanf (gone in 2.7.0)
- ruby-shell (gone in 2.7.0)
- ruby-sync (gone in 2.7.0)
- ruby-thwait (gone in 2.7.0)

Ruby 2.7.0 also dropped profile.rb and profiler.rb (they were in ruby-debuglib)

Patches changes:
- Dropped patch 001_fix_isnan_isinf_finite_with_uclibc.patch (now in release)
- Added 100-musl.patch, fixing mainly coroutine implementation selection

Helper scripts changes:
- ruby_missingfiles: do not ignore ruby-dev files
- ruby_find_pkgsdeps: better detect circular dependencies

Ruby 2.7.1 fixes these security issues:

* CVE-2020-10663: Unsafe Object Creation Vulnerability in JSON (Additional fix)
* CVE-2020-10933: Heap exposure vulnerability in the socket library

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>