Add RuboCop config and GitHub Actions worklfow

start running RuboCop against Pliny itself.

Author: beanieboi

.github/workflows/lint.yml

@@ -0,0 +1,34 @@
+name: Lint
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+permissions:
+  checks: write
+  contents: read
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: ['3.2', '3.3', '3.4']
+
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          fetch-depth: 0
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+          bundler-cache: true
+      - uses: wearerequired/lint-action@v2
+        with:
+          auto_fix: false
+          rubocop: true
+          rubocop_auto_fix: false
+          rubocop_command_prefix: bundle exec

.rubocop.yml

@@ -0,0 +1 @@
+inherit_from: .rubocop_todo.yml