Configure dependency license check workflows to allow "Licensed" install via Gem

The "Licensed" tool is used to check the project's compatibility with the licensing of its dependencies.

This tool is installed by the dependency license check GitHub Actions workflow using the `licensee/setup-licensed`
GitHub Actions action. This action attempts the installation according to the following procedure:

1. Install the Ruby gem.
2. If gem installation fails, install the pre-built executable from the GitHub release asset in the `licensee/licensed`
repo.

Previously, the first of these installation methods was failing:

```text
/usr/bin/gem install licensed -v 3.9.1
ERROR:  While executing gem ... (Gem::FilePermissionError)
    You don't have write permissions for the /var/lib/gems/3.2.0 directory.
	/usr/lib/ruby/vendor_ruby/rubygems/installer.rb:713:in `verify_gem_home'
	/usr/lib/ruby/vendor_ruby/rubygems/installer.rb:903:in `pre_install_checks'
	/usr/lib/ruby/vendor_ruby/rubygems/installer.rb:303:in `install'
	/usr/lib/ruby/vendor_ruby/rubygems/resolver/specification.rb:105:in `install'
	/usr/lib/ruby/vendor_ruby/rubygems/request_set.rb:195:in `block in install'
	/usr/lib/ruby/vendor_ruby/rubygems/request_set.rb:183:in `each'
	/usr/lib/ruby/vendor_ruby/rubygems/request_set.rb:183:in `install'
	/usr/lib/ruby/vendor_ruby/rubygems/commands/install_command.rb:215:in `install_gem'
	/usr/lib/ruby/vendor_ruby/rubygems/commands/install_command.rb:231:in `block in install_gems'
	/usr/lib/ruby/vendor_ruby/rubygems/commands/install_command.rb:224:in `each'
	/usr/lib/ruby/vendor_ruby/rubygems/commands/install_command.rb:224:in `install_gems'
	/usr/lib/ruby/vendor_ruby/rubygems/commands/install_command.rb:170:in `execute'
	/usr/lib/ruby/vendor_ruby/rubygems/command.rb:328:in `invoke_with_build_args'
	/usr/lib/ruby/vendor_ruby/rubygems/command_manager.rb:253:in `invoke_command'
	/usr/lib/ruby/vendor_ruby/rubygems/command_manager.rb:193:in `process_args'
	/usr/lib/ruby/vendor_ruby/rubygems/command_manager.rb:151:in `run'
	/usr/lib/ruby/vendor_ruby/rubygems/gem_runner.rb:52:in `run'
	/usr/bin/gem:12:in `<main>'
gem installation was not successful
```

So it falls back on the second installation method. That method works fine when using a version of "Licensed" <4.0.0.
However, starting from version 4.0.0, pre-built executable are no longer provided, so the only available installation
method for modern versions of "Licensed" is via the Ruby gem.

The gem failure can be avoided by setting up an accessible installation of Ruby in the runner machine, which is
accomplished using the "ruby/setup-ruby" action in a step preceding the `licensee/setup-licensed` step in the workflow.

Author: per1234

.github/workflows/check-go-dependencies-task.yml

@@ -72,6 +72,12 @@ jobs:
         with:
           submodules: recursive
 
+      # This is required to allow licensee/setup-licensed to install Licensed via Ruby gem.
+      - name: Install Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ruby # Install latest version
+
       - name: Install licensed
         uses: licensee/setup-licensed@v1.3.2
         with:
@@ -123,6 +129,12 @@ jobs:
         with:
           submodules: recursive
 
+      # This is required to allow licensee/setup-licensed to install Licensed via Ruby gem.
+      - name: Install Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ruby # Install latest version
+
       - name: Install licensed
         uses: licensee/setup-licensed@v1.3.2
         with: