Update cri-tools to v1.18.0-100-g2bf7674 for Go 1.15 compatibility
full diff:
set -eu -o pipefail
go get -u github.com/onsi/ginkgo/ginkgo
-CRITEST_COMMIT=16911795a3c33833fa0ec83dac1ade3172f6989e
+CRITEST_COMMIT=2bf7674922a424337d7580a08166d666c6802818 # v1.18.0-100-g2bf7674
go get -d github.com/kubernetes-sigs/cri-tools/...
cd "$GOPATH"/src/github.com/kubernetes-sigs/cri-tools
git checkout $CRITEST_COMMIT
