cargo: Add os::android-apis category

Since this crate provides access/interop to an Android-specific (OS)
API, use the new `os::android-apis` category that I recently upstreamed
at rust-lang/crates.io#8558.  That'll make this
crate show up at https://crates.io/categories/os::android-apis going
forward.

Cargo.toml

@@ -9,7 +9,7 @@ description = """
 A logging implementation for `log` which hooks to android log output.
 """
 keywords = ["android", "bindings", "log", "logger"]
-categories = ["api-bindings"]
+categories = ["api-bindings", "os::android-apis"]
 edition = "2021"
 
 [features]