add script to automate incrementing updater version number

scripts/updater_version.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+new_version=$1
+
+# Substitute version number
+current_ver="$(sed 's/[-<!CURR_VER:> ]//g' <<< $(sed -n '/CURR_VER/p' website/index.html))"
+sed -i -e "s/$current_ver/$new_version/g" website/index.html
+
+# Build website and push to GitHub
+parcel build website/index.html -d website/dist --public-url ./
+git add website/*
+git commit -m "website: change updater version number"
+git push
+git subtree push --prefix website/dist origin gh-pages