Comply with Golang semantic import versioning (#630)

* Code: compatible with semantic import versioning

* Tools & Docs: compatible with semantic import versioning

* Clean go.mod & go.sum

pkg/webdav/xml.go

@@ -32,7 +32,7 @@ import (
 	// In the long term, this package should use the standard library's version
 	// only, and the internal fork deleted, once
 	// https://github.com/golang/go/issues/13400 is resolved.
-	ixml "github.com/HFO4/cloudreve/pkg/webdav/internal/xml"
+	ixml "github.com/cloudreve/Cloudreve/v3/pkg/webdav/internal/xml"
 )
 
 // http://www.webdav.org/specs/rfc4918.html#ELEMENT_lockinfo