Change URI to IRI after finding validation pattern

commonAttributes.go

@@ -3,7 +3,7 @@ package atomfeed
 import "fmt"
 
 type CommonAttributes struct {
-	Base                URI                   `xml:"base,attr,omitempty"`
+	Base                IRI                   `xml:"base,attr,omitempty"`
 	Lang                LanguageTag           `xml:"lang,attr,omitempty"`
 	UndefinedAttributes []*ExtensionAttribute `xml:",any"`
 }