chore: upgrade supported language versions (#594)

Author: childish-sambino

.github/workflows/test-and-deploy.yml

@@ -17,7 +17,7 @@ jobs:
     timeout-minutes: 20
     strategy:
       matrix:
-        ruby: [ 2.4, 2.5, 2.6, 2.7, '3.0', ruby-head, jruby-9.2 ]
+        ruby: [ '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', 'ruby-head', 'jruby-9.2' ]
     steps:
       - name: Checkout twilio-ruby
         uses: actions/checkout@v2

README.md

@@ -25,6 +25,7 @@ This library supports the following Ruby implementations:
 * Ruby 2.6
 * Ruby 2.7
 * Ruby 3.0
+* Ruby 3.1
 
 ### Migrating from 4.x