Update to 8.16.2 and add 13.3.0

Author: DamianSzymanski

cookbooks/travis_ci_sardonyx/attributes/default.rb

@@ -58,9 +58,10 @@
 override['leiningen']['user'] = 'travis'
 
 override['travis_build_environment']['nodejs_versions'] = %w[
+  13.3.0
   12.13.1
   11.15.0
-  8.12.0
+  8.16.2
 ]
 override['travis_build_environment']['nodejs_default'] = '12.13.1'