🌱 Remove empty Makefile target

[oscr]

What this PR does / why we need it:

Minor cleanup that removes an empty Makefile entry Targets: from make help.

Current main branch

Usage:
  make <target>

Targets:

generate:
  generate                                       Run all generate-manifests-*, generate-go-deepcopy-*, generate-go-conversions-* and generate-go-openapi targets
(...)

With pr

Usage:
  make <target>

generate:
  generate                                       Run all generate-manifests-*, generate-go-deepcopy-*, generate-go-conversions-* and generate-go-openapi targets
(...)

[sbueringer]

sgtm

/lgtm

[vincepri]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: vincepri

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