unknown directive: toolchain

[DWay17]

Describe the bug
try to call go install and got:

go: errors parsing go.mod:
/lazydocker-git/go.mod:5: unknown directive: toolchain

go version go1.13.8 linux/amd64

To Reproduce
checkout

Expected behaviour
installed binary

Desktop (please complete the following information):

• The last commit id if you built project from sources (run : git rev-parse HEAD)
  7e7aadc

Additional context
Add any other context about the problem here.