v0.80.0

Changelog

• ce2fc88: A grant row may name a group, admitting its members through the closure (#48) (@mattblr)
• d82f3b7: Duplicate maps on one object is a compile error, not a silent policy replace (#49) (@mattblr)
• a4274f2: Release v0.80.0 (@mattblr)
• 51606d1: Write down the release steps, including the tag this repo needs twice (@mattblr)