Use closure instead of reference to closure in run_until_cancelled() (#236)

## Description

This adjusts the signature of `ServerRunner::run_until_cancelled()` to
avoid an unnecessary reference.

Co-authored-by: Uwe Klotz <uwe.klotz@gmail.com>

Author: sgoll

CHANGELOG.md

@@ -24,6 +24,8 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - Breaking: Remove methods `ua::DataValue::status_code()` and `ua::DataValue::with_status_code()`
   deprecated in 0.7.1. Use `status()` and/or `with_status()` instead.
 - Breaking: Remove method `ua::String::as_slice()` deprecated in 0.5.0. Use `as_bytes()` instead.
+- Breaking: Adjust signature of `ServerRunner::run_until_cancelled()` to use closure instead of a
+  reference to a closure.
 - Breaking: Bump Minimum Supported Rust Version (MSRV) to 1.83.
 - Rename `ServerRunner::run()` to `ServerRunner::run_until_interrupt()`. Deprecate former method.
 - Mark `AsyncMonitoredItem::into_stream()` as deprecated. Use the `Stream` implementation of this

src/server.rs

@@ -1546,7 +1546,7 @@ impl ServerRunner {
     /// # Errors
     ///
     /// This fails when the server cannot be started.
-    pub fn run_until_cancelled(self, is_cancelled: &mut impl FnMut() -> bool) -> Result<()> {
+    pub fn run_until_cancelled(self, mut is_cancelled: impl FnMut() -> bool) -> Result<()> {
         let Self {
             server,
             access_control_sentinel,