Update package version number

Set version number back to reflect movement to Sunfish.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ts-sunfish",
-  "version": "0.9.0",
+  "version": "0.7.0",
   "description": "an interpreter for the ¤><> esolang written in TypeScript",
   "main": "dist/main.js",
   "type": "module",