test(cli): Add tests for vault-ssh-certificate credential library

This adds tests for updating specific fields of the credential library.

internal/tests/cli/boundary/_credential_libraries.bash

@@ -5,6 +5,11 @@ function create_vault_ssh_certificate_library() {
     create vault-ssh-certificate $@
 }
 
+function update_vault_ssh_certificate_library() {
+  boundary credential-libraries \
+    update vault-ssh-certificate $@
+}
+
 function create_vault_generic_library() {
   boundary credential-libraries \
     create vault-generic $@