CI: Publish to RubyGems

.github/workflows/ruby.yml

@@ -37,3 +37,26 @@ jobs:
       run: bundle exec rake
     - name: Run checks
       run: test/run
+
+  publish:
+    needs: test
+
+    runs-on: ubuntu-latest
+
+    if: success() && github.event_name == 'push'
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: '3.1'
+        bundler-cache: true # runs 'bundle install' and caches installed gems automatically
+    - name: Publish to RubyGems
+      run: |
+        mkdir -p $HOME/.gem
+        printf -- "---\n:rubygems_api_key: ${GEM_HOST_API_KEY}\n" > $HOME/.gem/credentials
+        chmod 0600 $HOME/.gem/credentials
+        bundle exec rake publish
+      env:
+        GEM_HOST_API_KEY: "${{ secrets.RUBYGEMS_API_KEY }}"

Rakefile

@@ -20,7 +20,7 @@ file 'man/colorls.1' => ['man/colorls.1.ronn', 'lib/colorls/flags.rb'] do
 
   flags = ColorLS::Flags.new
   attributes = {
-    date: Date.iso8601(`git log -1 --pretty=format:%cI -- man/colorls.1`),
+    date: Date.iso8601(`git log -1 --pretty=format:%cI -- lib/colorls/flags.rb`),
     manual: 'colorls Manual',
     organization: "colorls #{ColorLS::VERSION}"
   }

colorls.gemspec

@@ -27,13 +27,13 @@ POST_INSTALL_MESSAGE = %(
 
 # rubocop:disable Metrics/BlockLength
 Gem::Specification.new do |spec|
-  is_tagged = ENV['TRAVIS_TAG'] == "v#{ColorLS::VERSION}"
-  is_origin = ENV['TRAVIS_REPO_SLUG'] == 'athityakumar/colorls'
-  build_number = ENV['TRAVIS_BUILD_NUMBER']
+  is_tagged = ENV['GITHUB_REF'] == "refs/tags/v#{ColorLS::VERSION}"
+  is_origin = ENV['GITHUB_REPOSITORY_OWNER'] == 'athityakumar'
+  build_number = ENV['GITHUB_RUN_NUMBER']
 
   spec.name          = 'colorls'
   spec.version       = if build_number && is_origin && !is_tagged
-                         # Prereleasing on Travis CI
+                         # Prereleasing on Github
                          digits = ColorLS::VERSION.to_s.split '.'
                          digits[-1] = digits[-1].to_s.succ