Rename parseFidoSerNumExtension to parseFidoSernumExtension

"sernum" feels like an atomic term in this case, especially with the background
of the OID label `id-fido-gen-ce-sernum`.

Author: emlun

webauthn-server-attestation/src/main/java/com/yubico/webauthn/attestation/CertificateUtil.java

@@ -45,7 +45,7 @@ private static byte[] parseSerNum(byte[] bytes) {
     }
   }
 
-  public static Optional<ByteArray> parseFidoSerNumExtension(X509Certificate cert) {
+  public static Optional<ByteArray> parseFidoSernumExtension(X509Certificate cert) {
     return Optional.ofNullable(cert.getExtensionValue(ID_FIDO_GEN_CE_SERNUM))
         .map(CertificateUtil::parseSerNum)
         .map(ByteArray::new);

webauthn-server-attestation/src/test/scala/com/yubico/webauthn/attestation/CertificateUtilSpec.scala

@@ -69,7 +69,7 @@ class CertificateUtilSpec
 
           val result =
             CertificateUtil
-              .parseFidoSerNumExtension(cert)
+              .parseFidoSernumExtension(cert)
               .toScala
           result should equal(Some(sernum))
       }
@@ -80,7 +80,7 @@ class CertificateUtilSpec
         TestAuthenticator.generateAttestationCertificate(extensions = Nil)
       val result =
         CertificateUtil
-          .parseFidoSerNumExtension(cert)
+          .parseFidoSernumExtension(cert)
           .toScala
       result should be(None)
     }
@@ -107,7 +107,7 @@ class CertificateUtilSpec
 
       val result =
         CertificateUtil
-          .parseFidoSerNumExtension(cert)
+          .parseFidoSernumExtension(cert)
           .toScala
 
       result should equal(Some(ByteArray.fromHex("01AFCEFB")))