add a script to update golang version

scripts/update_golang_version.sh

@@ -0,0 +1,29 @@
+#!/bin/sh
+
+golang_version="$1"
+
+current_version=$(grep -o -e 'golang:[.0-9]*' .circleci/config.yml | head -n1 | cut -d: -f2)
+
+# To support both GNU and BSD sed, the regex is looser than it needs to be.
+# Specifically, we use "* instead of "?, which relies on GNU extension without much loss of
+sed -i'' -e "s|golang:[.0-9]*|golang:${golang_version}|g" \
+       	.circleci/config/config.yml .circleci/config.yml
+sed -i'' -e "s|GOLANG_VERSION:[ \"]*[.0-9]*\"*|GOLANG_VERSION: ${golang_version}|g" \
+	.circleci/config/config.yml .circleci/config.yml
+
+sed -i'' -e "s|\\(golang.org.*version\\) [.0-9]*|\\1 ${golang_version}|g" \
+	README.md
+
+sed -i'' -e "s|go[.0-9]*.windows-amd64.zip|go${golang_version}.windows-amd64.zip|g" \
+	appveyor.yml
+
+sed -i'' -e "s|go_version=\"*[^\"]*\"*$|go_version=\"${golang_version}\"|g" \
+	scripts/vagrant-linux-priv-go.sh scripts/release/mac-remote-build
+
+# check if there is any remaining references to old versions
+if git grep -I --fixed-strings "${current_version}" | grep -v -e CHANGELOG.md -e vendor/
+then
+	echo "  ^^ files contain references to old golang version" >&2
+	echo "  update script and run again" >&2
+	exit 1
+fi