fix the source code directory after the soft link

To solve the problem of the disk full of code, I used soft links to move the directory where the code is saved, but the import path of the code generated by goctl is wrong

The problem occurs in tools/goctl/rpc/generator/mkdir.go SetPbDir()

d.ctx.Dir calculates the absolute path
pbDir does not calculate the absolute path
strings.TrimPrefix tries to remove d.ctx.Dir from pbDir but does not get a match

tools/goctl/rpc/generator/genpb.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	"github.com/zeromicro/go-zero/tools/goctl/rpc/execx"
+	"github.com/zeromicro/go-zero/tools/goctl/util/pathx"
 )
 
 // GenPb generates the pb.go file, which is a layer of packaging for protoc to generate gprc,