Update Rubies in CI (#35)

Author: leoarnold

.github/workflows/test.yml

@@ -18,7 +18,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.4.10", "2.5.8", "2.6.6", "2.7.2", "3.0.0", "jruby-9.2"]
+        ruby:
+          - 2.4.10
+          - 2.7.8
+          - 3.0.6
+          - 3.1.4
+          - 3.2.3
+          - 3.3.0
+          - jruby-9.2
+          - jruby-9.4
         command: ["bundle exec rake test"]
         include:
           - ruby: "head"

README.md

@@ -1,6 +1,6 @@
 # AST
 
-[![Build Status](https://travis-ci.org/whitequark/ast.svg?branch=master)](https://travis-ci.org/whitequark/ast)
+![.github/workflows/test.yml](https://github.com/whitequark/ast/actions/workflows/test.yml/badge.svg)
 [![Code Climate](https://codeclimate.com/github/whitequark/ast.svg)](https://codeclimate.com/github/whitequark/ast)
 [![Coverage Status](https://coveralls.io/repos/whitequark/ast/badge.svg?branch=master)](https://coveralls.io/r/whitequark/ast)