Update font-kit requirement from 0.6.0 to 0.7.0

Updates the requirements on [font-kit](https://github.com/servo/font-kit) to permit the latest version.
- [Release notes](https://github.com/servo/font-kit/releases)
- [Commits](https://github.com/servo/font-kit/commits/v0.7.0)

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

Author: dependabot-preview[bot]

Cargo.toml

@@ -25,7 +25,7 @@ features = ["std"]
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 rusttype = { version = "0.8.2", optional = true }
 lazy_static = { version = "1.4.0", optional = true }
-font-kit = { version = "0.6.0", optional = true }
+font-kit = { version = "0.7.0", optional = true }
 piston_window = { version = "0.108.0", optional = true }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies.image]