⚠️ Infrastructure provider DigitalOcean was renamed to digitalocean (previously do)

[prksu]

What this PR does / why we need it:

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

Cherry-pick of #3809

/assign @vincepri

[k8s-ci-robot]

@prksu: The following test failed, say /retest to rerun all failed tests:

Test name	Commit	Details	Rerun command
pull-cluster-api-apidiff-release-0-3	969cbbb	link	/test pull-cluster-api-apidiff-release-0-3

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[fabriziopandini]

/lgtm

api-diff failures are expected and documented with :warning

 Incompatible changes:
  - DOProviderName: value changed from "do" to "digitalocean"

[vincepri]

/approve
/lgtm
/milestone v0.3.11

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: vincepri

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