Add OID for User ID

Signed-off-by: Micah N Gorrell <micah.gorrell@venafi.com>
diff --git a/library/oid.c b/library/oid.c
index 14a1a92..472c038 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -238,6 +238,10 @@
         "pseudonym",
     },
     {
+        OID_DESCRIPTOR( MBEDTLS_OID_UID,            "id-uid",                         "User Id" ),
+        "uid",
+    },
+    {
         OID_DESCRIPTOR( MBEDTLS_OID_DOMAIN_COMPONENT, "id-domainComponent",           "Domain component" ),
         "DC",
     },