Switch to Github Actions and update supported Ruby versions

.github/workflows/CI.yml

@@ -0,0 +1,38 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - '2.5'
+          - '2.6'
+          - '2.7'
+          - '3.0'
+          - ruby-head
+    continue-on-error: ${{ matrix.ruby == 'ruby-head' }}
+    services:
+      memcached:
+        image: memcached
+        ports:
+          - 11211:11211
+      redis:
+        image: redis
+        ports:
+          - 6379:6379
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+      - run: |
+          bundle exec rake

.travis.yml

@@ -1,9 +0,0 @@
-language: ruby
-rvm:
-  - 2.2.6
-  - 2.3.7
-  - 2.4.4
-  - 2.5.1
-services:
-  - memcached
-  - redis-server

suo.gemspec

@@ -19,14 +19,14 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
-  spec.required_ruby_version = "~> 2.0"
+  spec.required_ruby_version = ">= 2.5"
 
   spec.add_dependency "dalli"
   spec.add_dependency "redis"
   spec.add_dependency "msgpack"
 
   spec.add_development_dependency "bundler"
-  spec.add_development_dependency "rake", "~> 10.0"
+  spec.add_development_dependency "rake", "~> 13.0"
   spec.add_development_dependency "rubocop", "~> 0.49.0"
   spec.add_development_dependency "minitest", "~> 5.5.0"
   spec.add_development_dependency "codeclimate-test-reporter", "~> 0.4.7"