Fix glob pattern when gcs url path has a trailing slash (#406)

Author: kafonek

img2dataset/reader.py

@@ -57,7 +57,7 @@ def __init__(
         self.tmp_path = tmp_path
 
         if fs.isdir(url_path):
-            self.input_files = sorted(fs.glob(url_path + "/*." + input_format))
+            self.input_files = sorted(fs.glob(url_path.rstrip("/") + "/*." + input_format))
             if len(self.input_files) == 0:
                 raise ValueError(f"No file found at path {url_path} with extension {input_format}")
         else: