Force async-io v1.3.1 in proxy-attestation-server.
@@ -48,6 +48,8 @@ actix-web = "2.0.0"
actix-rt = "1.0.0"
actix-http = "1.0"
async-std = "1.5"
+# Force the version os async-io.
+async-io = "=1.3.1"
env_logger = "0.7"
err-derive = "0.2"
serde_cbor = {version = "0.11", optional = true }
