fix(thumb blob path): separators be wrongly modified (#3062) (#3116)

* fix(thumb blob path): separators be wrongly modified

* Update common.go

pkg/util/common.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"math/rand"
+	"path"
 	"path/filepath"
 	"regexp"
 	"strconv"
@@ -164,7 +165,7 @@ func ReplaceMagicVar(rawString string, fsSeparator string, pathAvailable bool, b
 			return match
 		case "{blob_path}":
 			if blobAvailable {
-				return filepath.Dir(completeBlobPath) + fsSeparator
+				return path.Dir(completeBlobPath) + fsSeparator
 			}
 			return match
 		default: