ci: let bundler-cache: true to install gems (#40)

* ci: let bundler-cache: true to install gems

Signed-off-by: Kentaro Hayashi <hayashi@clear-code.com>

* ci: add Ruby 3.1 or later

Signed-off-by: Kentaro Hayashi <hayashi@clear-code.com>

* ci: add Ruby 4.0

Signed-off-by: Kentaro Hayashi <hayashi@clear-code.com>

---------

Signed-off-by: Kentaro Hayashi <hayashi@clear-code.com>

Author: kenhys

.github/workflows/linux.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ '2.4', '2.5', '2.6', '2.7', '3.0' ]
+        ruby: [ '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3', '3.4', '4.0' ]
         postgres: [ '9', '10', '11', '12', '13' ]
         os:
           - ubuntu-latest
@@ -32,6 +32,7 @@ jobs:
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
+        bundler-cache: true
     - name: prepare database
       env:
         PGPASSWORD: password
@@ -42,6 +43,4 @@ jobs:
       env:
         CI: true
       run: |
-        gem install bundler rake
-        bundle install --jobs 4 --retry 3
         bundle exec rake test