rake.yml in jekyll-plantuml-1.4.1

- old
+ new

@@ -18,7 +18,8 @@
     steps:
       - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
+      - run: sudo apt-get -y install plantuml
       - run: bundle update
       - run: bundle exec rake