unit.yml in watir-6.19.0

- old
+ new

@@ -16,10 +16,16 @@
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
       - run: bundle install
-      - run: bundle exec rake spec:unit
+      - uses: ./.github/actions/install-chrome
+      - run: Xvfb :99 &
+      - run: |
+          bundle exec rake spec:unit
+        env:
+          DISPLAY: :99
+
   linter-test:
     name: Rubocop Tests
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2