fix: add hardcoded utc prefix to crontab

[njtran]

Fixes #943

Description
Karpenter releases are built with UTC, but this adds a "TZ=UTC" prefix to valid schedules for budgets to ensure that the underlying cron library always parses the schedule in UTC time.

How was this change tested?
make apply with kwok and test different schedules.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[coveralls]

Pull Request Test Coverage Report for Build 8148257585

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.02%) to 81.024%

---

Files with Coverage Reduction	New Missed Lines	%
pkg/controllers/node/termination/terminator/eviction.go	2	88.79%

Totals
Change from base Build 8145053360:	0.02%
Covered Lines:	8164
Relevant Lines:	10076

---

💛 - Coveralls

[engedaam]

LGTM 🚀
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: engedaam, njtran

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [njtran]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[engedaam]

/lgtm