Minor link fix in deployment docs

[OlafSzmidt]

What this PR does / why we need it: The link for GCE section was broken. Minor fix.

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

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[k8s-reviewable]

This change is 

[OlafSzmidt]

/assign @aledbf

[coveralls]

Coverage decreased (-0.03%) to 39.709% when pulling 64db789 on OlafSzmidt:patch-1 into c1d541c on kubernetes:master.

[aledbf]

/approve

[aledbf]

@OlafSzmidt thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, OlafSzmidt

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