Add list of submitters to kyber768/META.yml

Separating this into principal and auxiliary submitters was
chosen by NIST. If we do not do the same thing, we would have to
decide how to order names. People seem to have opinions on ordering.

crypto_kem/kyber768/clean/META.yml

@@ -1,6 +1,17 @@
 name: Kyber768
 type: kem
 version: https://github.com/pq-crystals/kyber/commit/ab996e7460e5356b0e23aa034e7c2fe6922e60e6
-claimed_nist_level: 3
-length_public_key: 1088
-length_ciphertext: 1152
+claimed-nist-level: 3
+length-public-key: 1088
+length-ciphertext: 1152
+principal-submitter: Peter Schwabe
+auxiliary-submitters:
+  - Roberto Avanzi
+  - Joppe Bos
+  - Léo Ducas
+  - Eike Kiltz
+  - Tancrède Lepoint
+  - Vadim Lyubashevsky
+  - John M. Schanck
+  - Gregor Seiler
+  - Damien Stehlé