Add tool to bump version & create PR

This includes a tool to update the various files in the repo that need
to change when a version increments.

It also includes a workflow to trigger the action manually, passing it a
version & a changelog url. It'll update the values, build the app, build
the doc, make a commit in a branch, and create a pull request to merge
this stuff back into dev.

tools/bump-version/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "update-version",
+  "version": "1.0.0",
+  "type": "module",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "command-line-args": "^5.2.0",
+    "node-pandoc": "^0.3.0"
+  }
+}