Run CI on GitHub.

.github/workflows/ci.yml

@@ -0,0 +1,39 @@
+# This workflow runs continuous CI across different versions of ruby on all branches and pull requests to develop.
+
+name: CI
+on:
+  push:
+    branches: [ '**' ]
+  pull_request:
+    branches: [ develop ]
+  workflow_dispatch:
+
+jobs:
+  tests:
+    name: Ruby ${{ matrix.ruby }}
+    if: "contains(github.event.commits[0].message, '[ci skip]') == false"
+    runs-on: ubuntu-latest
+    env:
+      CI: true
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - 2.4
+          - 2.5
+          - 2.6
+          - 2.7
+          - ruby-head
+          - jruby
+    steps:
+      - name: Clone repository
+        uses: actions/checkout@v2
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+      - name: Install dependencies
+        run: bundle install --jobs 4 --retry 3
+      - name: Run tests
+        run: bundle exec rspec spec
+

README.md

@@ -4,7 +4,7 @@ An implementation of the JSON Canonicalization Scheme for Ruby
 Implements version 5 of [draft-rundgren-json-canonicalization-scheme-05](https://tools.ietf.org/html/draft-rundgren-json-canonicalization-scheme-05#page-5).
 
 [![Gem Version](https://badge.fury.io/rb/json-canonicalization.png)](http://badge.fury.io/rb/json-canonicalization)
-[![Build Status](https://travis-ci.org/dryruby/json-canonicalization.png?branch=master)](http://travis-ci.org/dryruby/json-canonicalization)
+[![Build Status](https://github.com/dryruby/json-canonicalization/workflows/CI/badge.svg?branch=develop)](https://github.com/dryruby/json-canonicalization/actions?query=workflow%3ACI)
 [![Coverage Status](https://coveralls.io/repos/dryruby/json-canonicalization/badge.svg)](https://coveralls.io/r/dryruby/json-canonicalization)
 
 # Description

json-canonicalization.gemspec

@@ -19,7 +19,7 @@ Gem::Specification.new do |gem|
 
   gem.required_ruby_version = '>= 2.4'
   gem.requirements          = []
-  gem.add_development_dependency 'rspec',           '~> 3.9'
+  gem.add_development_dependency 'rspec',           '~> 3.10'
   gem.add_development_dependency 'yard' ,           '~> 0.9'
 
   gem.post_install_message  = nil