Bump octokit from 4.12.0 to 4.13.0

Bumps octokit from 4.12.0 to 4.13.0.

Release notes

Sourced from octokit's releases.

v4.13.0

Bug fixes

• Fixes 422 error for passing client_id when making a new OAuth Authorization #1077 (tarebyte)

Documentation

• Add Octopoller section to readme #1073 (BenEmdon)

Support for new preview headers

• Add new strict validation preview header #1078 (tarebyte)

Testing fixes

• Update WebMock and VCR / update Octokit::Client::Authorizations spec #1077 (tarebyte)

Commits

• 737748e Release 4.13.0
• 9a04a38 Release v4.13.0
• 841dd32 Merge pull request #1077 from octokit/tarebyte/vcr-webmock-update
• 89095bc Merge branch 'master' into tarebyte/vcr-webmock-update
• 130726e Merge pull request #1078 from octokit/tarebyte/strict-validation-preview
• cd410f7 Add new strict validation preview header
• 9b28b00 Ok remove pry-byebug until we drop these versions of ruby
• 516ec61 Add conditional to not require pry-byebug unless it's in JRuby
• 565d5c0 Ensure pry-byebug is not used in jruby
• 8ba4ea8 Add another filter
• Additional commits viewable in compare view