Update Variable Classes

What's Changed

• update viz by @profjsb in #15
• add PR checker by @profjsb in #16
• grant write permission on PR by @profjsb in #19
• add permissions to test pr by @profjsb in #20
• Stellar variable label updates by @bfhealy in #18

New Contributors

• @bfhealy made their first contribution in #18

Full Changelog: v0.1.4...v0.1.5