v0.4.12

What's changed

• A bucket object with no extension opens as the same file on disk would: Parquet in place, anything else downloaded and read by its bytes, or shown as hex, instead of failing as Parquet
• Open all says what it reads (3 CSV files, 1 JSON file skipped) instead of mixed files, and is no longer offered on a bucket prefix that holds only sub-prefixes or nothing it can read