Fix MSRV test of `lightning-transaction-sync` with `esplora-async`

`lightning-transaction-sync`'s `esplora-async` dependency
indirectly depends on `tokio-util`, which, like tokio, recently
bumped its MSRV.

Here we update `ci/ci-tests.sh` to pin `tokio-util` to make MSRV
builds pass.

diff --git a/ci/ci-tests.sh b/ci/ci-tests.sh
index aff1a46c49e631ad3914793f90da62715da8bb12..0177112201744737d1f281a84fe6dad2f1a3e0bc 100755 (executable)
--- a/ci/ci-tests.sh
+++ b/ci/ci-tests.sh
@@ -11,6 +11,9 @@ function PIN_RELEASE_DEPS {
        # Starting with version 1.39.0, the `tokio` crate has an MSRV of rustc 1.70.0
        [ "$RUSTC_MINOR_VERSION" -lt 70 ] && cargo update -p tokio --precise "1.38.1" --verbose
 
+       # Starting with version 0.7.12, the `tokio-util` crate has an MSRV of rustc 1.70.0
+       [ "$RUSTC_MINOR_VERSION" -lt 70 ] && cargo update -p tokio-util --precise "0.7.11" --verbose
+
        return 0 # Don't fail the script if our rustc is higher than the last check
 }