Release 0.4

[msiglreith]

• Update raw-window-handle dep to 0.5.0.
• API changes (function removed, signature changes)
• minor path release Upgrade cocoa to 0.25 and core-graphics to 0.23 #10
• Upgrade raw-window-handle to 0.6.0 #8 (comment)

[msiglreith]

Created branch 0.3 with backported dep update

[msiglreith]

0.3.2 is now availabe https://crates.io/crates/raw-window-metal

[msiglreith]

0.4.0 should be also now available at crates.io with rwh:0.6