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/conf/conf.go

@@ -1,7 +1,7 @@
 package conf
 
 import (
-	"github.com/HFO4/cloudreve/pkg/util"
+	"github.com/cloudreve/Cloudreve/v3/pkg/util"
 	"github.com/go-ini/ini"
 	"gopkg.in/go-playground/validator.v9"
 )
@@ -34,7 +34,7 @@ type ssl struct {
 }
 
 type unix struct {
-    Listen string
+	Listen string
 }
 
 // slave 作为slave存储端配置