v0.1.1

What's Changed

• docs: update in readme by @yuanbohan in #54
• feat: define ExprVisitor trait and implement walk_expr by @waynexia in #60
• feat: impl extension expr node by @waynexia in #62
• refactor: merge agg and match to LabelModifier by @yuanbohan in #63
• feat: change value type Display behavior by @yuanbohan in #64
• chore: upgrade crate version by @yuanbohan in #65

Full Changelog: v0.1.0...v0.1.1