Fix CI toolchain drift failures

The PR was failing before it reached the PyYAML regression tests in two
places: the cp38 manylinux1 job installed latest cibuildwheel, whose 4.x
series no longer supports Python 3.8, and the Windows arm64 libyaml build
used a newer CMake that rejects libyaml 0.2.5's old minimum policy version.

Pin the cp38 manylinux1 job to cibuildwheel<4, pass
CMAKE_POLICY_VERSION_MINIMUM=3.5 to the Windows libyaml configure step,
and disable fail-fast for the Windows libyaml matrix so one architecture
does not hide the others.

Author: ingydotnet

.github/workflows/ci.yaml

@@ -145,7 +145,7 @@ jobs:
       with:
         matrix_yaml: |
           include:
-          - { platform: manylinux1, arch: x86_64, spec: cp38 }
+          - { platform: manylinux1, arch: x86_64, spec: cp38, cibw_version: 'cibuildwheel<4' }
           - { platform: manylinux1, arch: x86_64, spec: cp39, omit: ${{ env.skip_ci_redundant_jobs }} }
           - { platform: manylinux2014, arch: x86_64, spec: cp310, omit: ${{ env.skip_ci_redundant_jobs }} }
           - { platform: manylinux2014, arch: x86_64, spec: cp311, omit: ${{ env.skip_ci_redundant_jobs }} }
@@ -450,6 +450,7 @@ jobs:
     name: libyaml windows ${{ matrix.arch }}
     runs-on: ${{ (matrix.arch == 'arm64') && 'windows-11-arm' || 'windows-2022' }}
     strategy:
+      fail-fast: false
       matrix:
         include:
         - arch: x64
@@ -481,7 +482,7 @@ jobs:
         mkdir libyaml/build
 
         pushd libyaml/build
-        cmake.exe -G "Visual Studio 17 2022" -A ${{ matrix.arch }} -DYAML_STATIC_LIB_NAME=yaml ..
+        cmake.exe -G "Visual Studio 17 2022" -A ${{ matrix.arch }} -DYAML_STATIC_LIB_NAME=yaml -DCMAKE_POLICY_VERSION_MINIMUM=3.5 ..
         cmake.exe --build . --config Release
         popd