CI: Update Windows runner from deprecated 2019 to oldest available 2022.

Author: microbit-carlos

.github/workflows/build.yml

@@ -10,7 +10,7 @@ jobs:
   build-py-script:
     strategy:
       matrix:
-        os: [ubuntu-22.04, macos-13, windows-2019]
+        os: [ubuntu-22.04, macos-13, windows-2022]
         gcc: ['6-2016-q4', 'latest']  # Min version 6.2 as used in pext/yotta:latest docker image
         cmake: ['3.6.0', '']  # Empty string installs the latest CMake release
         exclude: