.travis.yml in cose-0.7.0 vs .travis.yml in cose-0.8.0

@@ -1,28 +1,35 @@
 sudo: false
 language: ruby
+cache: bundler
 
 rvm:
   - ruby-head
-  - 2.6.2
+  - 2.7.0-preview1
+  - 2.6.3
   - 2.5.5
   - 2.4.6
   - 2.3.8
   - 2.2.10
 
 gemfile:
-  - gemfiles/openssl_2_0.gemfile
+  - gemfiles/openssl_head.gemfile
   - gemfiles/openssl_2_1.gemfile
+  - gemfiles/openssl_2_0.gemfile
   - gemfiles/openssl_default.gemfile
 
 before_install: gem install bundler -v '~> 1.17'
 
 matrix:
   fast_finish: true
   allow_failures:
     - rvm: ruby-head
+    - rvm: 2.7.0-preview1
     - rvm: 2.2.10
+    - gemfile: gemfiles/openssl_head.gemfile
   exclude:
     - rvm: 2.2.10
-      gemfile: gemfiles/openssl_2_0.gemfile
+      gemfile: gemfiles/openssl_head.gemfile
     - rvm: 2.2.10
       gemfile: gemfiles/openssl_2_1.gemfile
+    - rvm: 2.2.10
+      gemfile: gemfiles/openssl_2_0.gemfile