How to use go packages with DO Functions?

How can external libraries from Go can be used in the FAAS product? I.e. running the following function:

package main

import "github.com/sirupsen/logrus"

func Main(args map[string]interface{}) map[string]interface{} {
	name, ok := args["name"].(string)
	if !ok {
		name = "stranger"
	}
	msg := make(map[string]interface{})
	msg["body"] = "Hello " + name + "!"
	logrus.Fatal("FAAS can't be used with external Go libraries like github.com/sirupsen/logrus i.e.")
	return msg
}

leads to the following error:

stderr: exec__.go:3:8: no required module provides package github.com/sirupsen/logrus; to add it:
stderr:  go get github.com/sirupsen/logrus
stderr: failed go build -o /tmp/action/1/bin/exec -ldflags -s -w 
stderr: in /tmp/action/1/src 
stderr: env {'GOROOT': '/usr/local/go', 'GOPATH': '/tmp/go', 'GO111MODULE': 'on', 'GOCACHE': '/tmp', 'PATH': '/go/bin:/usr/local/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin'}
stderr: 
stderr: The action did not initialize or run as expected. Log data might be missing.

After adding a go.mod / go.sum, the same error occured.

Help is really appreciated! Thanks in advance.