chore: Use bitnami docker image for kubectl

[souleb]

This will enable having dependabot automatic updates for docker images.

[coveralls]

Pull Request Test Coverage Report for Build 11439289064

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 11 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.2%) to 60.25%

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Files with Coverage Reduction	New Missed Lines	%
pkg/state/state_ipoib_network.go	4	75.24%
controllers/ipoibnetwork_controller.go	7	77.38%

Totals
Change from base Build 11406344448:	-0.2%
Covered Lines:	3321
Relevant Lines:	5512

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💛 - Coveralls

[adrianchiris]

LGTM.

@e0ne BTW didnt we want to switch to a client-go binary to avoid using kubectl ?

[rollandf]

/retest-image_scan

[e0ne]

We don't need this once #1118 will be merged