chore: drop cairo-rs dep and update gio to 0.15.0 (#124)

Fixes #123

Author: subpop

Cargo.toml

@@ -10,7 +10,6 @@ members = [ "tools", "ffi", "backend", "widgets" ]
 
 [dependencies]
 cascade = "1"
-cairo-rs = "0.14.0"
 futures = "0.3.13"
 gtk = { version = "0.15.0", features = ["v3_22"] }
 libc = "0.2"
@@ -29,7 +28,7 @@ i18n-embed-fl = "0.5.0"
 rust-embed = { version = "5.9.0", features = ["debug-embed"] }
 
 [build-dependencies]
-gio = "0.14.0"
+gio = "0.15.0"
 
 [target.'cfg(target_os = "windows")'.dependencies]
 winreg = "0.8"