Bump bundler version to latest

We are seeing a bunch of warnings when running the tests.
Bumping bundler's version fix them.

Because bundler's latest version does not support Ruby 3.0,
I had to add the CI workaround until 3.0 is not supported
anymore.

Author: stefannibrasil

.github/workflows/ruby.yml

@@ -53,7 +53,13 @@ jobs:
         ruby-version: ${{ matrix.ruby }}
 
     - name: Install dependencies
-      run: bundle install
+      run:  |
+        if [[ "${{ matrix.ruby }}" < "3.1" ]]; then
+          gem install bundler:2.4.22
+          bundle _2.4.22_ install
+        else
+          bundle install
+        fi
 
     - name: Run tests
       run: bundle exec rake test

Gemfile.lock

@@ -87,4 +87,4 @@ DEPENDENCIES
   yard (= 0.9.37)
 
 BUNDLED WITH
-   2.4.22
+  4.0.3