Bump actions/checkout to v6 and drop bundler/gem_tasks

Releases now run from CI via OIDC, so the local rake release/build/install
tasks are no longer needed. Build locally with 'gem build sparoid.gemspec'
if needed.

Author: oskgu360

.github/workflows/main.yml

@@ -14,7 +14,7 @@ jobs:
         ruby: [ 3.2, 3.3, 3.4, 4.0, ruby-head ]
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}

.github/workflows/release.yml

@@ -12,7 +12,7 @@ jobs:
       contents: write
       id-token: write
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: '3.4'

Rakefile

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require "bundler/gem_tasks"
 require "rake/testtask"
 
 Rake::TestTask.new(:test) do |t|