.travis.yml in airbrussh-1.3.1 vs .travis.yml in airbrussh-1.3.2

@@ -3,40 +3,43 @@
 cache: bundler
 rvm:
   - 1.9
   - 2.0
   - 2.1
-  - 2.2.9
-  - 2.3.6
-  - 2.4.3
-  - 2.5.0
+  - 2.2.10
+  - 2.3.8
+  - 2.4.5
+  - 2.5.3
   - ruby-head
 env:
   - sshkit="master"
   - sshkit="= 1.7.1"
   - sshkit="= 1.6.1"
 matrix:
   exclude:
     # Older versions of SSHKit don't work with Ruby 2.4+, so skip those
-    - rvm: 2.4.3
+    - rvm: 2.4.5
       env: sshkit="= 1.7.1"
-    - rvm: 2.4.3
+    - rvm: 2.4.5
       env: sshkit="= 1.6.1"
-    - rvm: 2.5.0
+    - rvm: 2.5.3
       env: sshkit="= 1.7.1"
-    - rvm: 2.5.0
+    - rvm: 2.5.3
       env: sshkit="= 1.6.1"
     - rvm: ruby-head
       env: sshkit="= 1.7.1"
     - rvm: ruby-head
       env: sshkit="= 1.6.1"
     # Newer versions of SSHKit don't work with Ruby 1.9
     - rvm: 1.9
       env: sshkit="master"
   include:
-    # Run Danger only once, on 2.4.3
-    - rvm: 2.4.3
+    # Run Danger only once, on 2.4.5
+    - rvm: 2.4.5
       script: bundle exec danger
 
 before_install:
-  - gem update --system
-  - gem install bundler --no-document
+  - gem update --system || echo "skipping rubygems upgrade"
+  - gem install bundler -v 1.17.3 --conservative --no-document
+  - gem install executable-hooks --conservative --no-document
+install:
+  - bundle _1.17.3_ install --jobs=3 --retry=3 --path=${BUNDLE_PATH:-vendor/bundle} || bundle install --jobs=3 --retry=3 --path=${BUNDLE_PATH:-vendor/bundle}