CI: Switch to macOS 26 runner

closes: #18775

Signed-off-by: Philip H. <[email protected]>
Signed-off-by: Christian Brabandt <[email protected]>

Author: pheiduck

.github/workflows/ci.yml

@@ -406,7 +406,7 @@ jobs:
       fail-fast: false
       matrix:
         features: [tiny, normal, huge]
-        runner: [macos-15-intel, macos-15]
+        runner: [macos-15-intel, macos-26]
 
     steps:
       - name: Checkout repository from github