Update CI and rake task definitions

Author: epaew

.github/workflows/main.yml

@@ -0,0 +1,32 @@
+name: RSpec
+
+on:
+  pull_request: {}
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    name: RSpec with Ruby ${{ matrix.ruby }}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - '2.7'
+          - '3.0'
+          - '3.1'
+          - '3.2'
+          - '3.3'
+          - '3.4'
+          - '4.0'
+
+    steps:
+      - uses: actions/checkout@v6
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - run: bundle exec rspec

.github/workflows/rspec.yaml

@@ -0,0 +1,20 @@
+name: RuboCop
+
+on:
+  pull_request: {}
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    name: RuboCop
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 4.0
+          bundler-cache: true
+
+      - run: bundle exec rubocop

.github/workflows/rubocop.yaml

@@ -0,0 +1,20 @@
+name: Steep
+
+on:
+  pull_request: {}
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    name: Steep
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 3.0
+          bundler-cache: true
+
+      - run: bundle exec steep

.github/workflows/steep.yaml

@@ -1,8 +1,12 @@
 # frozen_string_literal: true
 
 require "bundler/gem_tasks"
+require "rspec/core/rake_task"
 require "rubocop/rake_task"
+require "steep/rake_task"
 
+RSpec::Core::RakeTask.new(:rspec)
 RuboCop::RakeTask.new
+Steep::RakeTask.new
 
-task default: :rubocop
+task default: %i[rubocop steep rspec]