(MODULES-11365) Updates Windows nightly tests

Newer versions of Ruby used by the setup-ruby action use the ucrt
C library. Puppet nightly gems are instead built with the mscvcrt
library (AKA mingw), which causes

This commit updates the GitHub Action that tests nightly Puppet gems
to use the generic gem instead of the mingw gem, and adds a step to
install the ffi dependency that was included in the mingw gem but not
the generic gem.

Author: mhashizume

.github/workflows/unit_tests_with_nightly_puppet_gem.yaml

@@ -31,7 +31,11 @@ jobs:
           - os: 'windows-2022'
             os_type: 'Windows'
             env_set_cmd: '$env:'
-            gem_file: 'puppet-latest-x64-mingw32.gem'
+            # setup-ruby uses ucrt for newer Rubies, but we only support mingw
+            # in our Windows Puppet nightly gems. For now, we'll just install
+            # the universal gem and manually install the ffi dependency
+            gem_file: 'puppet-latest.gem'
+            extra_steps: 'gem install ffi --version 1.15.5'
 
     runs-on: ${{ matrix.os }}
     steps:
@@ -45,6 +49,7 @@ jobs:
 
       - name: Install the latest nightly build of puppet${{ matrix.puppet_version }} gem
         run: |
+          ${{ matrix.extra_steps }}
           curl https://nightlies.puppet.com/downloads/gems/puppet${{ matrix.puppet_version }}-nightly/${{ matrix.gem_file }} --output puppet.gem --location
           gem install puppet.gem -N