Update E2E test instructions on README.md

[Victoremepunto]

The README.md end-to-end testing section mentions a deprecated way of running end-to-end tests in this project, that was removed a while ago, without updating the README to explain how to run the tests locally.

The README.md needs to be updated to reflect how to run E2E tests locally.

[openshift-bot]

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/lifecycle stale

[openshift-bot]

Stale issues rot after 30d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.
Exclude this issue from closing by commenting /lifecycle frozen.

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/lifecycle rotten
/remove-lifecycle stale

[Victoremepunto]

/remove-lifecycle rotten

this issue is still relevant and should be resolved with #277

[openshift-bot]

Issues go stale after 90d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.
Exclude this issue from closing by commenting /lifecycle frozen.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[openshift-bot]

Stale issues rot after 30d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.
Exclude this issue from closing by commenting /lifecycle frozen.

If this issue is safe to close now please do so with /close.

/lifecycle rotten
/remove-lifecycle stale