Bump gfx-backend-metal from 0.6.4 to 0.6.5

Bumps [gfx-backend-metal](https://github.com/gfx-rs/gfx) from 0.6.4 to 0.6.5.
- [Release notes](https://github.com/gfx-rs/gfx/releases)
- [Changelog](https://github.com/gfx-rs/gfx/blob/master/CHANGELOG.md)
- [Commits](https://github.com/gfx-rs/gfx/commits)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Cargo.lock

@@ -2075,9 +2075,9 @@ dependencies = [
 
 [[package]]
 name = "gfx-backend-metal"
-version = "0.6.4"
+version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60ba1c77c112e7d35786dbd49ed26f2a76ce53a44bc09fe964935e4e35ed7f2b"
+checksum = "273d60d5207f96d99e0d11d0718995f67e56533a9df1444d83baf787f4c3cb32"
 dependencies = [
  "arrayvec 0.5.1",
  "bitflags",