Support HSC PDR3

What's Changed

• Adds tool to download PSFs in bulk by @EiffL in #24
• Add s21a by @Tang-SL in #27
• Apply the package to HSC PDR3 data by @DenekoW in #29

New Contributors

• @Tang-SL made their first contribution in #27
• @DenekoW made their first contribution in #29

Full Changelog: 0.1.2...0.1.3