Auto merge of #58 - sotaroikeda:upgleam, r=glennw

Update gleam to v0.4

Fixes #57.

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Cargo.toml

@@ -3,15 +3,15 @@ name = "io-surface"
 description = "Bindings to IO Surface for OS X"
 homepage = "https://github.com/servo/io-surface-rs"
 repository = "https://github.com/servo/io-surface-rs"
-version = "0.6.0"
+version = "0.7.0"
 authors = ["The Servo Project Developers"]
 license = "MIT / Apache-2.0"
 
 [dependencies]
 libc = "0.2"
-gleam = "0.2"
+gleam = "0.4"
 
 [target.x86_64-apple-darwin.dependencies]
 core-foundation = "0.3"
-cgl = "0.1.4"
+cgl = "0.2.1"
 leaky-cow = "0.1.1"