Install previous version of winflexbison

CI fails to install winflexbison because of checksum mismatch.
Change to install previous version to fix it.

See: https://github.com/ruby/lrama/actions/runs/7429169162/job/20217621117

.github/workflows/test.yaml

@@ -35,7 +35,7 @@ jobs:
         with:
           ruby-version: ${{ matrix.ruby }}
           bundler-cache: true
-      - run: choco install winflexbison || choco install winflexbison
+      - run: choco install winflexbison --version=2.4.8.20170203 || choco install winflexbison --version=2.4.8.20170203
       - run: win_flex --help
       - run: bundle install
       - run: bundle exec rspec