E2E: bump e2etest version and use new field

[karampok]

With the new version we need to change the .IP of the neighbor to .ID. The struct in metallb/e2etest looks as follows:

type Neighbor struct {
	// ID is the key that vtysh returns for the neighbor,
	// it can be either IP or interface name if unnumbered.
	ID                      string
	VRF                     string

Is this a BUG FIX or a FEATURE ?:

Uncomment only one, leave it on its own line:

/kind failing

/kind documentation
/kind regression

What this PR does / why we need it:

Special notes for your reviewer:

Release note:

NONE

[karampok]

@oribon this is needed because of the change we did on the other repo about .IP to become .ID and string.
Thanks!

[karampok]

Given there are some other changes in the go.mod,
I bump as follow

#fix the go.mod to look to main
        go.universe.tf/e2etest => github.com/metallb/metallb/e2etest  main

and execute go mod tidy which fixes the version but as side effect some other stuff are needed.

[karampok]

As @oribon suggested that to be merged either with the #212 or with #231