vendor: add buildkit

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/containerd/continuity/.travis.yml

@@ -0,0 +1,33 @@
+language: go
+sudo: required
+
+go:
+  - 1.9.x
+  - 1.10.x
+  - 1.11.x
+  - tip
+
+go_import_path: github.com/containerd/continuity
+
+env:
+# NOTE: we cannot set GOOS directly (because gimme overrides the value)
+  - TRAVIS_GOOS=windows
+  - TRAVIS_GOOS=linux
+  - TRAVIS_GOOS=darwin
+
+install:
+  - go get -u github.com/vbatts/git-validation
+  - go get -u github.com/kunalkushwaha/ltag
+  - go get -u github.com/LK4D4/vndr
+
+before_script:
+  - pushd ..; git clone https://github.com/containerd/project; popd
+
+script:
+  - export GOOS=${TRAVIS_GOOS}
+  - DCO_VERBOSITY=-q ../project/script/validate/dco
+  - ../project/script/validate/fileheader ../project/
+  - ../project/script/validate/vendor
+  - make build binaries
+  - if [ "$GOOS" = "linux" ]; then make vet test; fi
+  - if [ "$GOOS" != "linux" ]; then make test-compile; fi