Bump webmock from 3.6.0 to 3.7.1

Bumps webmock from 3.6.0 to 3.7.1.

Changelog

Sourced from webmock's changelog.

3.7.1

• Fixed Async::HTTP::Client adapter code to not cause Ruby warning

  Thanks to y-yagi

3.7.0

• Support for Async::HTTP::Client

  Thanks to Andriy Yanko

3.6.2

• Fixed Patron adapter to handle HTTP/2 status line.

  Thanks to Fábio D. Batista

3.6.1

• Fixed issue with matching Addressable::Template without a period in the domain

  Thanks to Eike Send

• Support for write_timeout in Net::HTTP

  Thanks to Claudio Poli

• Fixed issue with handling urls with ":80" or ":443" in the path.

  Thanks to Csaba Apagyi for reporting and to Frederick Cheung for fixing the issue.

Commits

• 8b0d6a5 Version 3.7.1
• 564cbb5 Merge pull request #842 from y-yagi/fix_ruby_warning
• 63a6376 Fix "warning: shadowing outer local variable - v"
• 91f05df Version 3.7.0
• c12dd19 Merge pull request #839 from ayanko/master
• e3a7d90 Add support for Async::HTTP::Client
• 2a2d3d8 Version 3.6.2
• 4907604 Merge pull request #834 from fabiob/fix-for-http2
• 833711e Use openjdk8 for now in travis.
• 2b4f3a4 Fix to support HTTP/2 status lines
• Additional commits viewable in compare view