Update RSpec syntax/usage

Fixes a deprecation warning

spec/jobs/create_ldap_user_job_spec.rb

@@ -4,7 +4,8 @@ RSpec.describe CreateLdapUserJob, type: :job do
   let(:ldap_client_mock) { instance_double(Net::LDAP) }
 
   subject(:job) {
-    described_class.any_instance.stub(:ldap_client).and_return(ldap_client_mock)
+    allow_any_instance_of(described_class).to receive(:ldap_client).and_return(ldap_client_mock)
+
     described_class.perform_later(
       'halfinney', 'kosmos.org', 'halfinney@example.com',
       'remember-remember-the-5th-of-november'
@@ -12,7 +13,11 @@ RSpec.describe CreateLdapUserJob, type: :job do
   }
 
   it "creates a new document with the correct attributes" do
-    ldap_client_mock.should_receive(:add).with(
+    allow(ldap_client_mock).to receive(:add) # spy on mock
+
+    perform_enqueued_jobs { job }
+
+    expect(ldap_client_mock).to have_received(:add).with(
       dn: "cn=halfinney,ou=kosmos.org,cn=users,dc=kosmos,dc=org",
       attributes: {
         objectclass: ["top", "account", "person", "extensibleObject"],
@@ -23,8 +28,6 @@ RSpec.describe CreateLdapUserJob, type: :job do
         userPassword: "remember-remember-the-5th-of-november"
       }
     )
-
-    perform_enqueued_jobs { job }
   end
 
   after do