pw_software_update/keygen: Call main()

No-Docs-Update-Reason: module is in early development
Change-Id: I5920dec12092910cbaf177c7eb485da1786e48e3
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/62082
Pigweed-Auto-Submit: Ali Zhang <alizhang@google.com>
Reviewed-by: Joe Ethier <jethier@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/pw_software_update/py/pw_software_update/keygen.py b/pw_software_update/py/pw_software_update/keygen.py
index aa10dfb..265cc61 100644
--- a/pw_software_update/py/pw_software_update/keygen.py
+++ b/pw_software_update/py/pw_software_update/keygen.py
@@ -84,4 +84,4 @@
 
 if __name__ == '__main__':
     logging.basicConfig()
-    gen_ecdsa_sha2_nistp256_keypair(**vars(parse_args()))
+    main(**vars(parse_args()))