🌱 pr-verify: use env var for passing the PR title

[chrischdi]

What this PR does / why we need it:
Uses an environment variable for the pr-verifier.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Edit:
Thanks to @RedYetiDev for reporting!

Sorry that I forgot to add co-authored here. Will do it on the other PR's.

[neolit123]

/lgtm
/approve

thanks, SGTM.

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 265e759366e72ba6f9e53ba97ec0ded3c1207c88

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: neolit123

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[neolit123]

i guess this can be backported for a few "active" branches too?

[sbueringer]

/cherry-pick release-1.8

[sbueringer]

/cherry-pick release-1.7

[k8s-infra-cherrypick-robot]

@sbueringer: new pull request created: #11230

In response to this:

/cherry-pick release-1.8

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[k8s-infra-cherrypick-robot]

@sbueringer: new pull request created: #11231

In response to this:

/cherry-pick release-1.7

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[sbueringer]

We need this on all branches where we are using this action, but should be the same as the supported branches