Support Xcode 13.x

Changelog

v3.0.0 (Support Xcode 13.x)

Full Changelog

Implemented enhancements:

• Implement HPKP (HTTP Public Key Pinning) #20
• Add network reachability #18
• Increase test coverage #17

Fixed bugs:

• Update heroku ssl certificate #24

Closed issues:

• Remove integration with Travis #28
• Support Xcode 13.x #26
• Disable Reachability for watchOS #22
• Remove deprecated functions and classes #19

Merged pull requests:

• Increase test coverage (#17) #31 (billp)
• Remove integration with Travis (#28) #29 (billp)
• Issue 26 support Xcode 13.x #27 (billp)
• Update heroku ssl certificate (#24) #25 (billp)