Release version 0.6.0 of both libraries (#245)

This updates the version and syncs them in preparation for a new
release.

Author: mrobinson

harfbuzz-sys/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "harfbuzz-sys"
-version = "0.5.0"
+version = "0.6.0"
 edition = "2021"
 
 authors = ["The Servo Project Developers"]

harfbuzz-traits/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "harfbuzz-traits"
-version = "0.1.0"
+version = "0.6.0"
 edition = "2021"
 
 authors = ["The Servo Project Developers"]

harfbuzz/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "harfbuzz"
-version = "0.4.0"
+version = "0.6.0"
 edition = "2021"
 
 authors = ["The Servo Project Developers"]
@@ -15,12 +15,12 @@ categories = ["text-processing"]
 
 [dependencies.harfbuzz-sys]
 path = "../harfbuzz-sys"
-version = "0.5.0"
+version = "0.6.0"
 default-features = false
 
 [dependencies.harfbuzz-traits]
 path = "../harfbuzz-traits"
-version = "0.1.0"
+version = "0.6.0"
 default-features = false
 
 [features]