Fix wrong security level for FrodoKEM-976-AES

[skip ci]

crypto_kem/frodokem976aes/META.yml

@@ -1,6 +1,6 @@
 name: FrodoKEM-976-AES
 type: kem
-claimed-nist-level: 1
+claimed-nist-level: 3
 length-public-key: 15632
 length-secret-key: 31296
 length-ciphertext: 15744