Creation of build env fails

[ibazulic]

Currently, creation of builld environments fail due to cfssl requiring Go version 1.12+ and not 1.11.5 which is currently being used:

Step 15/24 : RUN go get -u github.com/cloudflare/cfssl/cmd/cfssl
 ---> Running in 8aab323e28fb
# github.com/cloudflare/cfssl/vendor/github.com/zmap/zlint/lints
go/src/github.com/cloudflare/cfssl/vendor/github.com/zmap/zlint/lints/result.go:75:9: undefined: strings.ReplaceAll

CFSSL readme file: https://github.com/cloudflare/cfssl
Related issue: cloudflare/cfssl#1028