ci: fix cirrus and reduce rebuilds (#2460)

* ci: fix Cirrus CI on Windows

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* ci: skip unrelated changes more often

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

---------

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

examples/cirrus-ci-minimal.yml

@@ -52,9 +52,13 @@ windows_x86_task:
     memory: 4G
 
   install_pre_requirements_script:
+    - certutil -generateSSTFromWU roots.sst
+    - certutil -addstore -f root roots.sst
+    - del roots.sst
     - choco install -y --no-progress python3 --version 3.12.4
     - refreshenv
-    - echo PATH=%PATH% >> "%CIRRUS_ENV%"
+    - powershell -Command "$cleanPath = $env:PATH -replace ';+$', ''; Add-Content -Path $env:CIRRUS_ENV -Value ('PATH=' + $cleanPath)"
+
   <<: *BUILD_AND_STORE_WHEELS
 
 macos_arm64_task: