V1: Add conversion for Task.Resources

[lbernick]

Changes

This commit adds support for Task.Resources when converting between v1beta1 and v1
versions of Tasks. This will allow us to release v1 Task in a backwards compatible way,
by ensuring that v1beta1 Tasks with Resources will have the Resources serialized into
annotations on the v1 Task on conversion.

Part n of #4546

/kind misc

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• n/a Has Docs included if any changes are user facing
• Has Tests included if any functionality added or changed
• Follows the commit message standard
• Meets the Tekton contributor standards (including
  functionality, content, code)
• Has a kind label. You can add one by adding a comment on this PR that contains /kind <type>. Valid types are bug, cleanup, design, documentation, feature, flake, misc, question, tep
• n/a Release notes block below has been updated with any user facing changes (API changes, bug fixes, changes requiring upgrade notices or deprecation warnings)
• n/a Release notes contains the string "action required" if the change requires additional action from users switching to the new release

Release Notes

NONE

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/apis/pipeline/v1beta1/task_conversion.go	97.4%	94.4%	-2.9
pkg/apis/version/conversion.go	Do not exist	0.0%

[lbernick]

/retest

filed #5254

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/apis/pipeline/v1beta1/task_conversion.go	97.4%	94.4%	-2.9
pkg/apis/version/conversion.go	Do not exist	81.2%

[abayer]

/approve
/retest

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: abayer

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Needs approval from an approver in each of these files:

• pkg/apis/OWNERS [abayer]

Approvers can indicate their approval by writing /approve in a comment
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[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/apis/pipeline/v1beta1/task_conversion.go	97.4%	94.4%	-2.9
pkg/apis/version/conversion.go	Do not exist	81.2%

[lbernick]

/retest

[abayer]

/lgtm