bump version to 0.4.0

Author: lukad

gleam.toml

@@ -1,5 +1,5 @@
 name = "pears"
-version = "0.3.0"
+version = "0.4.0"
 description = "A parser combinator library for Gleam"
 licences = ["MIT"]
 repository = { type = "github", user = "lukad", repo = "pears" }