v2.1.0: Drop Ruby 2.2 and RubyGems 2.3 and add support for Faraday 2

Breaking changes from 2.1.0

• Drop support RubyGems 2.3.x and earlier by @tnir in #428
• Drop Ruby 2.2 support by @tnir in #454

If you want to use Ruby 2.2 and/or RubyGems 2.3, stay at v2.0.0. Severe security and bugfixes will be available on 2.0.x branch in several monthes.
In case you missed it, please see breaking changes in 2.0.0 from 1.x: https://github.com/geminabox/geminabox/releases/tag/v2.0.0

What's Changed

Enhancements

• Allow admins to use Faraday v2 with Ruby 2.6+ by @tnir in #447
• Move require rss from code to test by @tnir in #448

Security

• Limit sinatra dependency to 2.x by dropping 1.x by @tnir in #446
• Drop Faraday v0 support by @tnir in #458

Bugfixes

• Eliminate a faraday 1.x deprecation warning by @skaes in #385

Document

• Simplify system requirements: Ruby and RubyGems by @tnir in #440
• Update system requirements with RubyGems 2.4 or higher by @tnir in #444

Chore

• Prepare 2.0.1 by @tnir in #438
• Move to normal for actions/stale only for PRs by @tnir in #439
• Prepare 2.1.0 by @tnir in #441
• Remove IncomingGem code for RubyGems 1.x by @tnir in #442
• Update RuboCop from 1.30.1 to 1.31.0 by @tnir in #445
• Set TargetRubyVersion to 2.3 for RuboCop by @tnir in #455
• Enable Bundler/OrderedGems cop by @tnir in #456
• Relax multipart-post gem used in tests by @tnir in #457
• Update gemspec to date by @tnir in #459
• Prepare 2.1.0.rc.1 by @tnir in #460
• Release 2.1.0 by @tnir in #463

Full Changelog: v2.0.0...v2.1.0