drop unused OWNERS files and update script (#3064)

hack/OWNERS

@@ -1,10 +0,0 @@
-# The OWNERS file is used by prow to automatically merge approved PRs.
-
-approvers:
-- productivity-writers
-
-reviewers:
-- productivity-reviewers
-
-labels:
-- area/test-and-release

hack/update-k8s-deps.sh

@@ -1,29 +0,0 @@
-#!/usr/bin/env bash
-
-# Copyright 2020 The Knative Authors
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-set -o errexit
-set -o nounset
-set -o pipefail
-
-source $(dirname "$0")/../vendor/knative.dev/hack/library.sh
-
-run_go_tool knative.dev/test-infra/buoy \
-  buoy float ${REPO_ROOT_DIR}/go.mod \
-    --release "$1" --domain k8s.io --ruleset=Release \
-    | xargs -n1 -t go get -d
-
-./hack/update-deps.sh
-