[Bug] Add rt-tokio feature to aws-sdk-s3 (TraceMachina#1248)

Feature `rt-tokio` had been transitively dependended on,
durning refactors of `Cargo.toml` files it was accidentally
dropped.

Author: adam-singer

nativelink-store/Cargo.toml

@@ -14,7 +14,9 @@ async-trait = "0.1.80"
 aws-config = { version = "1.5.4", default-features = false, features = [
   "rustls",
 ] }
-aws-sdk-s3 = { version = "1.41.0", default-features = false }
+aws-sdk-s3 = { version = "1.41.0", features = [
+  "rt-tokio",
+], default-features = false }
 aws-smithy-runtime = { version = "1.6.2" }
 bincode = "1.3.3"
 blake3 = { version = "1.5.2", default-features = false }