Add validation for encryptionKeyCRN for VPC Machine spec

[ChandrikaHarish]

What this PR does / why we need it: IBM Cloud CRN validation regex added at the time of boot volume validation for the encryptionKeyCRN for VPC Machine spec . CRN regex added as referred from doc - https://cloud.ibm.com/apidocs/vpc/latest#get-volume

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

/area provider/ibmcloud

1. Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

Release note:

Add validation for encryptionKeyCRN for VPC Machine spec

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[k8s-ci-robot]

Hi @ChandrikaHarish. Thanks for your PR.

I'm waiting for a github.com member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[Amulyam24]

/ok-to-test

[ChandrikaHarish]

Tested the PR changes with CAPI cluster, screenshot of test results attached.

[Amulyam24]

/cc @anshuman-agarwala

can you PTAL?

[anshuman-agarwala]

This check is also applicable for AdditionalVolumes Can you please add it there as well.
Also added some minor comments.

[Amulyam24]

minor comment, LGTM!

Thanks @ChandrikaHarish !

[Amulyam24]

/lgtm

[Prajyot-Parab]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ChandrikaHarish, Prajyot-Parab

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