fix(ci): drop go module tidy check from travis

go modules leave checksums of old releases which gets removed when tidy is run, so the diff check is likely to pick us something every time a go module was bumped. Can't have it on CI this way as it will keep failing jobs

.travis.yml

@@ -77,8 +77,6 @@ jobs:
         - export GO111MODULE=on
         # compile assets via webpack and build those into bindata_assetfs.go file
         - make bindata_assetfs.go
-        # tidy module deps to ensure we only have what we needed (git diff will pick it up)
-        - go mod tidy -v
         # verify that there are no uncommited changes from (re)compiling sass
         # assets
         - git diff --exit-code