Bump pest dependency to `v2.5.1

Author: althonos

Cargo.toml

@@ -22,8 +22,8 @@ repository = "fastobo/horned-functional"
 status     = "actively-developed"
 
 [dependencies]
-pest = "2.1.0"
-pest_derive = "2.1.0"
+pest = "2.5.1"
+pest_derive = "2.5.1"
 horned-owl = "0.11.0"
 curie = "0.1.1"
 enum_meta = "0.6.0"