Fix Rubocop linter complaints

spec/models/clusters/applications/cert_manager_spec.rb

@@ -20,7 +20,7 @@ describe Clusters::Applications::CertManager do
   end
 
   describe '#install_command' do
-    let(:cluster_issuer_file) { {:"cluster_issuer.yaml" => "---\napiVersion: certmanager.k8s.io/v1alpha1\nkind: ClusterIssuer\nmetadata:\n  name: letsencrypt-prod\nspec:\n  acme:\n    server: https://acme-v02.api.letsencrypt.org/directory\n    email: admin@example.com\n    privateKeySecretRef:\n      name: letsencrypt-prod\n    http01: {}\n"} }
+    let(:cluster_issuer_file) { { "cluster_issuer.yaml": "---\napiVersion: certmanager.k8s.io/v1alpha1\nkind: ClusterIssuer\nmetadata:\n  name: letsencrypt-prod\nspec:\n  acme:\n    server: https://acme-v02.api.letsencrypt.org/directory\n    email: admin@example.com\n    privateKeySecretRef:\n      name: letsencrypt-prod\n    http01: {}\n" } }
     subject { cert_manager.install_command }
 
     it { is_expected.to be_an_instance_of(Gitlab::Kubernetes::Helm::InstallCommand) }