small fixes and dependency updates

vendor/github.com/pkg/sftp/request-plan9.go

@@ -1,10 +1,9 @@
+//go:build plan9
 // +build plan9
 
 package sftp
 
 import (
-	"path"
-	"path/filepath"
 	"syscall"
 )
 
@@ -15,20 +14,3 @@ func fakeFileInfoSys() interface{} {
 func testOsSys(sys interface{}) error {
 	return nil
 }
-
-func toLocalPath(p string) string {
-	lp := filepath.FromSlash(p)
-
-	if path.IsAbs(p) {
-		tmp := lp[1:]
-
-		if filepath.IsAbs(tmp) {
-			// If the FromSlash without any starting slashes is absolute,
-			// then we have a filepath encoded with a prefix '/'.
-			// e.g. "/#s/boot" to "#s/boot"
-			return tmp
-		}
-	}
-
-	return lp
-}