Add script to update-lock-files

Copy the script from `rust-bitcoin`, also add a `just` command to call
it.

contrib/update-lock-files.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+#
+# Update the minimal/recent lock file
+
+set -euo pipefail
+
+for file in Cargo-minimal.lock Cargo-recent.lock; do
+    cp --force "$file" Cargo.lock
+    cargo check
+    cp --force Cargo.lock "$file"
+done

justfile

@@ -32,3 +32,7 @@ sane: lint
 # Check for API changes.
 check-api:
   ./contrib/check-for-api-changes.sh
+
+# Update the lock files.
+update-lock-files:
+  ./contrib/update-lock-files.sh