(PDK-1108) Use idiomatic rspec-mocks

This commit updates the tests to use the anything matchcer instead of Object as
per recommended practice in rspec-mocks.

spec/unit/pdk/cli/set/config_spec.rb

@@ -67,7 +67,7 @@ def project_config
 
     RSpec.shared_examples 'a saved setting' do |setting_name, expected_value, force = nil|
       it 'saves the setting' do
-        expect(pdk_config).to receive(:set).with(setting_name, Object, force: force).and_call_original
+        expect(pdk_config).to receive(:set).with(setting_name, anything, force: force).and_call_original
         expect(run).to eq(0)
         expect(pdk_config.get(setting_name)).to eq(expected_value)
       end