RequestHeaders not copied when Lambda forks

[jonmarkprice]

When the timelimit is reached and Lambda forks, the request headers are not being copied over to arg.Flags.
The rest of the arguments are copied here:

goad/lambda/lambda.go

Line 565 in e015a55

func (l *goadLambda) getInvokeArgsForFork() invokeArgs {

Compare this to

goad/infrastructure/infrastructure.go

Line 28 in e015a55

func InvokeLambdas(inf Infrastructure) {

where Lambda is created for the first time, in particular. This loop

goad/infrastructure/infrastructure.go

Lines 55 to 57 in e015a55

	for _, v := range t.Headers {
	args = append(args, fmt.Sprintf("--header=%s", v))
	}

is missing from getInvokeArgsForFork.