Bump esplora-client to 0.11

.. the most-recent release, which also dropped the `async-std`
dependency in favor of a default sleeper implementation using `tokio`.

Author: tnull

lightning-transaction-sync/Cargo.toml

@@ -27,7 +27,7 @@ lightning = { version = "0.0.124", path = "../lightning", default-features = fal
 bitcoin = { version = "0.32.2", default-features = false }
 bdk-macros = "0.6"
 futures = { version = "0.3", optional = true }
-esplora-client = { version = "0.9", default-features = false, optional = true }
+esplora-client = { version = "0.11", default-features = false, optional = true, features = ["tokio"] }
 electrum-client = { version = "0.21.0", optional = true }
 
 [dev-dependencies]