.travis.yml in docurium-0.5.0 vs .travis.yml in docurium-0.6.0

- old
+ new

@@ -1,13 +1,14 @@
 language: ruby
+dist: xenial
+addons:
+  apt:
+    packages:
+      - libclang-6.0-dev
+      - llvm-6.0
 rvm:
- - ruby-2.0
- - ruby-2.1
+ - ruby-2.4
+ - ruby-2.5
  - ruby-head
- - rbx
 
 env:
- - LLVM_CONFIG=llvm-config-3.3
-
-before_install:
- - sudo apt-get update
- - sudo apt-get install libclang-3.3-dev llvm-3.3
+ - LLVM_CONFIG=llvm-config-6.0