.travis.yml in pg_objects-0.5.6 vs .travis.yml in pg_objects-0.5.7

@@ -1,9 +1,10 @@
 language: ruby
 rvm:
-  - 2.5.8
-  - 2.6.6
-  - 2.7.1
+  - 2.5.9
+  - 2.6.7
+  - 2.7.3
+  - 3.0.1
 before_install: gem install bundler -v 1.16.2
 script:
  - bundle exec rspec spec
  - bundle exec rubocop