Add release script

Author: shesek

release.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+set -eo pipefail
+set -x
+
+[ -z "$1" ] && { echo >&2 version required; exit 1; }
+
+sed -i 's!"version": ".*"!"version": "'"$1"'"!' composer.json
+sed -ri "s!Version:( *).*!Version:\\1$1!" woocommerce-gateway-lightning.php
+sed -ri s!download/v[^/]+/woocommerce-gateway-lightning.zip!download/v$1/woocommerce-gateway-lightning.zip! README.md
+
+./build.sh
+
+read -p "Release v$1 ready, press Enter to publish"
+
+git add README.md composer.json woocommerce-gateway-lightning.php
+git commit -m v$1 && git tag v$1
+git push && git push --tags
+
+echo Attach zip file: https://github.com/ElementsProject/woocommerce-gateway-lightning/releases/edit/v$1