.travis.yml in rasn1-0.7.0 vs .travis.yml in rasn1-0.7.1

@@ -3,8 +3,9 @@
   - 2.3
   - 2.4
   - 2.5
   - 2.6
 install:
-  - gem install bundler --version "~> 1.17.3"
-  - bundle _1.17.3_ install --path vendor/bundle --jobs=3 --retry=3
+  # new bundler install needed by ruby2.3 and 2.6(!)
+  - gem install bundler
+  - bundle install --path vendor/bundle --jobs=3 --retry=3