Bump bevy version, temporarily use git hash for kira_audio

Cargo.toml

 [package]
 name = "micro_bevy_musicbox"
-version = "0.1.0"
+version = "0.2.0-pre.1"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bevy = { version = "0.7", default-features = false }
-bevy_kira_audio = { version = "0.10", features = ["mp3"] }
+bevy = { version = "0.8", default-features = false }
+bevy_kira_audio = { git = "https://github.com/NiklasEi/bevy_kira_audio.git", features = ["mp3"], rev = "8e2ee7ffb675163cd01083d46f12aeba634f9f8f" }
 serde = "1"
 serde_json = "1"
\ No newline at end of file