Modernize workflows a little bit

Author: dentarg

.github/workflows/main.yml

@@ -4,7 +4,6 @@ on:
   push:
     branches:
       - main
-
   pull_request:
 
 jobs:
@@ -14,14 +13,16 @@ jobs:
     strategy:
       matrix:
         ruby:
-          - '3.3.5'
-
+          - 3.3
+          - 3.4
+          - ruby-head
     steps:
-    - uses: actions/checkout@v4
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@v1
+    - uses: actions/checkout@v6
+    - uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
         bundler-cache: true
-    - name: Run the default task
-      run: bundle exec rake
+    - run: bundle exec rake
+    # ensure gem can be built and installed
+    - run: gem build rubocop-eightyfourcodes
+    - run: gem install *.gem

.github/workflows/release.yml

@@ -6,14 +6,17 @@ on:
       - v*
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 jobs:
   release:
     if: github.repository == '84codes/rubocop-eighty-four-codes'
     runs-on: ubuntu-latest
     permissions:
       id-token: write # for trusted publishing
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true