Install Ninja in CI

actions/runner-images#8343 (comment)

Ninja's presence in the Windows images was due to it being a
transitive dependency of another packages. It was never guaranteed
to be present. The actions/runner-images devs do not plan on adding
it so we're forced to install it ourselves.

.github/workflows/ci.yml

@@ -117,7 +117,7 @@ jobs:
         max_attempts: 10
         timeout_minutes: 3
         command: |
-          choco install OpenCppCoverage -y
+          choco install ninja OpenCppCoverage -y
           echo "C:\Program Files\OpenCppCoverage" >> $env:GITHUB_PATH
 
     - name: Configure CMake