.travis.yml in jekyll-diagrams-0.5.0 vs .travis.yml in jekyll-diagrams-0.5.1

@@ -3,10 +3,16 @@
 rvm:
   - 2.4
   - 2.5
   - 2.6
 
+addons:
+  apt:
+    packages:
+      - graphviz
+      - python3
+      - python3-pip
+      - python3-setuptools
+
 before_install:
-  - sudo apt update && sudo apt install -y graphviz
-  - sudo apt install -y python3 python3-pip python3-setuptools
   - sudo pip3 install blockdiag seqdiag actdiag nwdiag
   - gem update --system && gem install bundler