chore: bump the localnet binary used in CI to v1.31.1-rc (#1453)

The committed GraphQL schema is generated from the 1.31.1 line, so the
pinned v1.29.0 node cannot serve 16 of the fields the client is compiled
against, and any test touching one fails against it.

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
Co-authored-by: Thibault Martinez <thibault@iota.org>

Author: 3 people

.github/actions/start-local-network/action.yml

@@ -32,7 +32,7 @@ runs:
         # tar -zxvf "$artifact_name.tgz" ./iota ./iota-localnet
 
         # Uncomment when using a released build
-        IOTA_BINARY_VERSION="v1.29.0"
+        IOTA_BINARY_VERSION="v1.31.1-rc"
         ASSET_NAME="iota-$IOTA_BINARY_VERSION-linux-x86_64.tgz"
         download_url="https://github.com/iotaledger/iota/releases/download/$IOTA_BINARY_VERSION/$ASSET_NAME"
         echo "Downloading binary from $download_url"