v1.17.0

• Fix CI which is broken on master #115 (by @kytrinyx)
• Silence warnings triggered by Ruby 2.7 #116 (by @kytrinyx)
• Update dependencies to be compatible with Ruby 2.7 #117 (by @kytrinyx)
• Update dotenv requirement from ~> 1.0 to ~> 2.7 #120 (dependabot)
• Update gem-release requirement from ~> 0.7 to ~> 2.1 #119 (dependabot)
• Update webmock requirement from ~> 1.21 to ~> 3.8 #118 (dependabot)
• Upgrade to Ruby 2.7 & incorporate a Dockerfile #121 (by @parkr & @MarkTiedemann)