Fix m.version to not depend on package.json (#2464)

* Fix `m.version` to not depend on `package.json`

Created an accidental breaking change.

* Update changelog

* Fix a failing test

scripts/update-version.js

@@ -0,0 +1,10 @@
+"use strict"
+
+const fs = require("fs")
+const version = require("../package.json").version
+const index = require.resolve("../index")
+
+fs.writeFile(index,
+	fs.readFile(index, "utf-8")
+		.replace(/(version\s*=\s*)(['"]).*?\2/, `$1$2${version}$2`)
+)