Add script to check go version and fix output directory permissions (#4907)

hack/check-go-version.sh

@@ -0,0 +1,45 @@
+#!/bin/bash
+
+# Copyright 2020 The Kubernetes 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.
+
+if [ -n "$DEBUG" ]; then
+	set -x
+fi
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+MINIMUM_GO_VERSION=go1.13
+
+if [[ -z "$(command -v go)" ]]; then
+    echo "
+Can't find 'go' in PATH, please fix and retry.
+See http://golang.org/doc/install for installation instructions.
+"
+    exit 1
+fi
+
+IFS=" " read -ra go_version <<< "$(go version)"
+
+if [[ "${MINIMUM_GO_VERSION}" != $(echo -e "${MINIMUM_GO_VERSION}\n${go_version[2]}" | sort -s -t. -k 1,1 -k 2,2n -k 3,3n | head -n1) && "${go_version[2]}" != "devel" ]]; then
+	echo "
+Detected go version: ${go_version[*]}.
+ingress-nginx requires ${MINIMUM_GO_VERSION} or greater.
+
+Please install ${MINIMUM_GO_VERSION} or later.
+"
+    exit 1
+fi