Drop 2.1.0, 2.2.0, and test with 2.2.5
Drop 2.1.0, 2.2.0, and test with 2.2.5

testfairy/dpl,travis-ci/dpl,mattk42/dpl,travis-ci/dpl,testfairy/dpl,testfairy/dpl,pengsrc/dpl,travis-ci/dpl,computology/dpl