.travis.yml in tdlib-ruby-2.1.0 vs .travis.yml in tdlib-ruby-2.2.0

@@ -1,9 +1,9 @@
 language: ruby
 rvm:
 - 2.4.9
-- 2.6.5
+- 2.7.0
 addons:
   apt:
     sources:
     - ubuntu-toolchain-r-test
     - llvm-toolchain-precise-3.8
@@ -17,9 +17,10 @@
   matrix:
   - CXX=clang++-3.8 CC=clang-3.8
   global:
     secure: DmAoRsr+dTPVNs486nBXzChjzCCVdoxfmSbvqMBBl0v8uuUIZD1rSfYKcEaL5pmE7vgYq3X+3Dk0gf4ef/p2xPVKqFKrkBiF/7t06WgQTH7003gHMLq3aC7R9+1xvqJDzpoc6UB59Y1fOJBe5YfqDuw1dT9a46tzY2uzoVpEpbN8M/hssaKf6Wuzvpz5yekFeXq2raPwi3aOqvkSG+ODoacVdYQgJ4Vn0//CI2HzWijkQCvdsefWQUKkbgtuLWRp3UNy8AEhVWzQnTcSM7oc+MwMsOI/90DZkTP5n2WJl/CFTM5b70VyrIciG92SvTAhhBo/p7t3QBJa6kJMPXAHh5q+3wqVQA411+CoVF48bO5rKjKY3Ply49uqAzVJRh+Tkhf5uC1pHiZ6QKGxu1Czde+mKItBpaDmJFmQi0CSdv2WYXLnJWOQIO6vc2P3liwpMDRDyaGWOQtUYS+gHAlRbD4NPycIkGjkcjmLMqSEEO1TdCpM+CYwTvNTkRS+9HrWXZNdEfWORDYHgYohoIP6kY6XWSgunUb6F6pVxLoPWJNEBEVuIMZeOa/s9oklxBzD5XXIzBx4QsPYanvfxoN1uOcXlBXbOGqwiqb+urokNDw+BzWhbA+xY03U2+yO0Ujh3HQDyMDtrXEQfaPC0SxpEvIINVYwznG4sMKvbOaCVSo=
 before_install:
+- gem install -v 2.1.2 bundler
 - set -e
 - cd td
 - mkdir -p build
 - cd build
 - cmake -DCMAKE_BUILD_TYPE=Release ..