Bump knative/pkg dependency, request apps/deployments RBAC permissions

[imjasonh]

This has the same effect as #610 but it should actually enforce validation webhooks and pass e2e tests

Proposed Changes

• dep ensure -update github.com/knative/pkg
• dep ensure -update github.com/knative/test-infra (not ultimately necessary, but it shouldn't hurt)
• Update pkg/reconciler/{build,buildtemplate,clusterbuildtemplate}/ to consume new simplified controller constructor (as #610)
• At this point, e2e tests fail :boom:
• Update config/200-clusterrole.yaml to request apps/deployments permissions instead of extensions/deployments (which is defunct) -- e2e tests pass :tada:

Release Note

Controller ClusterRole now requests `apps/deployments` permissions instead of defunct `extensions/deployments` -- these are necessary to enforce webhook validation.

cc @mattmoor

[knative-prow-robot]

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This pull-request has been approved by: ImJasonH, shashwathi

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