gem install binman fails to install

[kron4eg]

Here is the issue

$ gem in binman -V
HEAD https://api.rubygems.org/api/v1/dependencies
200 OK
GET https://api.rubygems.org/api/v1/dependencies?gems=binman
200 OK
Getting SRV record failed: DNS result has no information for _rubygems._tcp.api.rubygems.org
GET https://api.rubygems.org/api/v1/dependencies?gems=opener
200 OK
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/.gitignore
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/Gemfile
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/LICENSE
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/README.markdown
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/Rakefile
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/VERSION.markdown
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/bin/binman
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/bin/binman-help
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/bin/binman-html
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/bin/binman-rake
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/bin/binman-roff
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/bin/binman-show
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/bin/binman-text
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/binman.gemspec
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/lib/binman.rb
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/lib/binman/rakefile.rb
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/lib/binman/version.rb
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/man/index.html
/Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0/man/man0/README.html
ERROR:  While executing gem ... (Gem::Package::PathError)
    installing into parent path /Users/kron/.gem/ruby/2.3.0/README.markdown of /Users/kron/.gem/ruby/2.3.0/gems/binman-5.1.0 is not allowed

I've tried to install md2man, but got this problem.

[sunaku]

Thanks for your report. 👍 This is a known issue that can be solved by upgrading to RubyGems 2.5.2:

gem update --system