(maint) update travis to newer runner and ruby

This is based off puppetlabs/pdk-templates#318

.sync.yml

@@ -2,9 +2,8 @@
 ".gitlab-ci.yml":
   delete: true
 ".travis.yml":
-  global_env: 
+  global_env:
     - HONEYCOMB_WRITEKEY="7f3c63a70eecc61d635917de46bea4e6",HONEYCOMB_DATASET="litmus tests"
-  dist: trusty
   deploy_to_forge:
     enabled: false
   user: puppet

.travis.yml

@@ -1,6 +1,6 @@
 ---
 os: linux
-dist: trusty
+dist: xenial
 language: ruby
 cache: bundler
 before_install:
@@ -16,7 +16,7 @@ script:
   - 'SIMPLECOV=yes bundle exec rake $CHECK'
 bundler_args: --without system_tests
 rvm:
-  - 2.5.3
+  - 2.5.7
 env:
   global:
     - HONEYCOMB_WRITEKEY="7f3c63a70eecc61d635917de46bea4e6",HONEYCOMB_DATASET="litmus tests"
@@ -35,7 +35,7 @@ jobs:
       bundler_args: 
       dist: trusty
       env: PLATFORMS=travis_deb_puppet5
-      rvm: 2.5.3
+      rvm: 2.5.7
       script: ["bundle exec rake litmus:acceptance:parallel"]
       services: docker
       stage: acceptance
@@ -47,7 +47,7 @@ jobs:
       bundler_args: 
       dist: trusty
       env: PLATFORMS=travis_ub_puppet5
-      rvm: 2.5.3
+      rvm: 2.5.7
       script: ["bundle exec rake litmus:acceptance:parallel"]
       services: docker
       stage: acceptance
@@ -59,7 +59,7 @@ jobs:
       bundler_args: 
       dist: trusty
       env: PLATFORMS=travis_el6_puppet5
-      rvm: 2.5.3
+      rvm: 2.5.7
       script: ["bundle exec rake litmus:acceptance:parallel"]
       services: docker
       stage: acceptance
@@ -71,7 +71,7 @@ jobs:
       bundler_args: 
       dist: trusty
       env: PLATFORMS=travis_el7_puppet5
-      rvm: 2.5.3
+      rvm: 2.5.7
       script: ["bundle exec rake litmus:acceptance:parallel"]
       services: docker
       stage: acceptance
@@ -83,7 +83,7 @@ jobs:
       bundler_args: 
       dist: trusty
       env: PLATFORMS=travis_deb_puppet6
-      rvm: 2.5.3
+      rvm: 2.5.7
       script: ["bundle exec rake litmus:acceptance:parallel"]
       services: docker
       stage: acceptance
@@ -95,7 +95,7 @@ jobs:
       bundler_args: 
       dist: trusty
       env: PLATFORMS=travis_ub_puppet6
-      rvm: 2.5.3
+      rvm: 2.5.7
       script: ["bundle exec rake litmus:acceptance:parallel"]
       services: docker
       stage: acceptance
@@ -107,7 +107,7 @@ jobs:
       bundler_args: 
       dist: trusty
       env: PLATFORMS=travis_el6_puppet6
-      rvm: 2.5.3
+      rvm: 2.5.7
       script: ["bundle exec rake litmus:acceptance:parallel"]
       services: docker
       stage: acceptance
@@ -119,7 +119,7 @@ jobs:
       bundler_args: 
       dist: trusty
       env: PLATFORMS=travis_el7_puppet6
-      rvm: 2.5.3
+      rvm: 2.5.7
       script: ["bundle exec rake litmus:acceptance:parallel"]
       services: docker
       stage: acceptance
@@ -132,7 +132,7 @@ jobs:
       stage: spec
     -
       env: PUPPET_GEM_VERSION="~> 6.0" CHECK=parallel_spec
-      rvm: 2.5.3
+      rvm: 2.5.7
       stage: spec
 branches:
   only: