windows fix

Author: jhamman

src/zarr/storage/_zep8.py

@@ -317,11 +317,13 @@ def is_zep8_url(url: Any) -> bool:
             }
 
             # Check if adapter name looks like a ZEP 8 adapter and is not a standard scheme
+            # Exclude Windows drive letters (single letter followed by backslash or forward slash)
             if (
                 adapter_name
                 and adapter_name.lower() not in standard_schemes
                 and "/" not in adapter_name
                 and "\\" not in adapter_name
+                and not (len(adapter_name) == 1 and adapter_name.isalpha() and len(parts) == 2 and (parts[1].startswith("/") or parts[1].startswith("\\")))
                 and (
                     adapter_name.isalnum()
                     or adapter_name.replace("_", "").replace("-", "").isalnum()