Add git.RemoteTags() function

[puerco]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR adds a new function to the git package: git.RemoteTags() which queries the default remote repository and returns it's tags in a string slice.

It also modifies the git.LsRemote() function so that it honors Repo.maxRetries when performing the remote query.

Which issue(s) this PR fixes:

Related to #1595

Special notes for your reviewer:

Depends on #1621 to run

Does this PR introduce a user-facing change?

- New remote tag functions: `git.RemoteTags()` and `git.HasRemoteTag()` which return the tags in the default remote repository and check if one exists
- `git.LSRemote()` now honors `Repo.maxRetries` and will retry when a network failure occurs

[saschagrunert]

/lgtm
/hold
for rebase

[saschagrunert]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: puerco, saschagrunert

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• pkg/OWNERS [saschagrunert]

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[saschagrunert]

/hold cancel

[puerco]

/test pull-release-integration-test