Fix incorrect xsd:date regexp.

schemas.lv2/xsd.ttl

@@ -121,7 +121,7 @@ xsd:date
 	rdfs:label "date" ;
 	owl:withRestrictions (
 		[
-			xsd:pattern "-?[0-9][0-9][0-9][0-9]([0-9]*)?-(0[1-9]|1[0-1])-([0-3][1-9])([+-][0-1][0-9]:[0-6][0-9])?"
+			xsd:pattern "-?[0-9][0-9][0-9][0-9]([0-9]*)?-(0[1-9]|1[0-2])-([0-3][0-9])([+-]([0-1][0-9]|2[0-3]):[0-5][0-9])?"
 		]
 	) .