ci: move github runners from macos-11 to macos-14

Move the GitHub runners currently on macos-11 to macos-14 as the former is
no longer supported by GitHub.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

.github/workflows/devicetree_checks.yml

@@ -27,9 +27,9 @@ jobs:
     strategy:
       matrix:
         python-version: ['3.10', '3.11', '3.12']
-        os: [ubuntu-22.04, macos-11, windows-2022]
+        os: [ubuntu-22.04, macos-14, windows-2022]
         exclude:
-        - os: macos-11
+        - os: macos-14
           python-version: 3.6
         - os: windows-2022
           python-version: 3.6

.github/workflows/west_cmds.yml

@@ -30,9 +30,9 @@ jobs:
     strategy:
       matrix:
         python-version: ['3.10', '3.11', '3.12']
-        os: [ubuntu-22.04, macos-11, windows-2022]
+        os: [ubuntu-22.04, macos-14, windows-2022]
         exclude:
-        - os: macos-11
+        - os: macos-14
           python-version: 3.6
         - os: windows-2022
           python-version: 3.6