Replace async-std with tokio

Tokio is a far more mature async runtime.

Cargo.toml

@@ -21,7 +21,6 @@ categories = [
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-async-std = { version = "1.12.0", features = ["async-attributes", "attributes", "tokio1"] }
 clap = { version = "4.4.3", features = ["derive", "env", "wrap_help"] }
 simple_logger = { version = "4.2.0", features = ["timestamps", "colors", "stderr"] }
 http = "0.2.9"
@@ -35,7 +34,8 @@ thiserror = "1.0.48"
 toml = "0.8.0"
 url = { version = "2.4.1", features = ["serde"] }
 xdg = "2.5.2"
+tokio = { version = "1.32.0", features = ["macros"] }
 
 [dev-dependencies]
 mockito = "1.2.0"
-env_logger = "0.10.0"
+env_logger = "0.10.0"