Modernize Stage I (#5)

- Drop Ruby < 3.0 support
- Replace RestClient with Faraday
- Introduce RuboCop
- Drop dependency from Hashugar (didn't look to be used)

Close #1, close #3

.gitattributes

@@ -0,0 +1 @@
+.rubocop_todo.yml linguist-generated

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly

.github/workflows/rubocop.yml

@@ -0,0 +1,30 @@
+name: RuboCop
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    name: RuboCop
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Install libmagic-dev
+      run: |
+        sudo apt-get update
+        sudo apt-get -yq --no-install-suggests --no-install-recommends install libmagic-dev
+    - uses: actions/checkout@v4
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: '3.4'
+        rubygems: latest
+        bundler-cache: true
+    - name: RuboCop
+      run: bundle exec rubocop -f github

.github/workflows/ruby.yml

@@ -16,9 +16,13 @@ jobs:
 
     strategy:
       matrix:
-        ruby-version: ['2.3', '2.4', '2.5', '2.6', '2.7']
+        ruby-version: ['3.0', '3.1', '3.2', '3.3', '3.4']
         channel: [stable]
 
+        include:
+          - ruby-version: 'ruby-head'
+            channel: experimental
+
     continue-on-error: ${{ matrix.channel != 'stable' }}
 
     steps:

.rubocop.yml

@@ -0,0 +1,30 @@
+inherit_from: .rubocop_todo.yml
+
+require:
+  - rubocop-packaging
+  - rubocop-performance
+  - rubocop-rake
+  - rubocop-rspec
+
+AllCops:
+  NewCops: enable
+  TargetRubyVersion: 3.0
+  Exclude:
+    - .git/**/*
+    - .github/**/*
+    - gemfiles/**/*
+    - node_modules/**/*
+    - tmp/**/*
+    - vendor/**/*
+
+Layout/LineLength:
+  Enabled: false
+
+RSpec/ExampleLength:
+  Enabled: false
+
+RSpec/MultipleExpectations:
+  Enabled: false
+
+Style/ArgumentsForwarding:
+  Enabled: false