conformance: remove async main

Signed-off-by: Jack Leightcap <[email protected]>

Author: jleightcap

tests/conformance/Cargo.toml

@@ -9,7 +9,6 @@ license = "Apache-2.0"
 [dependencies]
 clap = { version = "4.0.8", features = ["derive"] }
 sigstore = { path = "../../" }
-tokio = { version = "1.17.0", features = ["rt"] }
 
 [[bin]]
 name = "sigstore"

tests/conformance/conformance.rs

@@ -104,7 +104,6 @@ struct VerifyBundle {
     artifact: String,
 }
 
-#[tokio::main]
-pub async fn main() {
+fn main() {
     let cli = Cli::parse();
 }