update glib version to 0.21.0, update crate version to 0.7.0

Author: yggverse

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ggemtext"
-version = "0.6.1"
+version = "0.7.0"
 edition = "2024"
 license = "MIT"
 readme = "README.md"
@@ -17,5 +17,5 @@ repository = "https://github.com/YGGverse/ggemtext"
 
 [dependencies.glib]
 package = "glib"
-version = "0.20.9"
+version = "0.21.0"
 features = ["v2_66"]