Update keywords and categories in Cargo.toml (#49)

Author: lizelive

oxisynth/Cargo.toml

@@ -5,7 +5,8 @@ edition = "2021"
 
 authors = ["Poly <marynczak.bartlomiej@gmail.com>"]
 description = "Rust soundfont synthesizer"
-keywords = ["audio", "soundfont"]
+keywords = ["soundfont", "midi", "synthesizer", "audio", "music"]
+categories = ["multimedia::audio"]
 license = "LGPL-2.1"
 repository = "https://github.com/PolyMeilex/oxisynth"
 documentation = "https://docs.rs/oxisynth"