cleanup: grant the correct permissions when creating a file

[chaosi-zju]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

cleanup: grant the correct permissions when creating a file

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 60.00000% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 53.31%. Comparing base (fcb46bb) to head (472da38).
Report is 2 commits behind head on master.

Files	Patch %	Lines
operator/pkg/util/util.go	0.00%	2 Missing ⚠️

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4960   +/-   ##
=======================================
  Coverage   53.31%   53.31%           
=======================================
  Files         252      252           
  Lines       20485    20489    +4     
=======================================
+ Hits        10921    10924    +3     
- Misses       8842     8844    +2     
+ Partials      722      721    -1     

Flag	Coverage Δ
unittests	53.31% <60.00%> (+<0.01%)	⬆️

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[RainbowMango]

/assign @zhzhuang-zju

[zhzhuang-zju]

cc @RainbowMango

[RainbowMango]

/lgtm
/approve

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RainbowMango

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Needs approval from an approver in each of these files:

• hack/OWNERS [RainbowMango]
• operator/OWNERS [RainbowMango]
• pkg/karmadactl/cmdinit/OWNERS [RainbowMango]
• pkg/util/OWNERS [RainbowMango]

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