Adding Explorer Context Menu

You can now do this automatically in UnityLauncher Settings tab!

---

If you want to add registry entry manually:

You can add custom context menu item into windows Explorer to quickly open current folder as an unity project (with correct unity version automatically)

Instructions: https://stackoverflow.com/questions/20449316/how-add-context-menu-item-to-windows-explorer-for-folders/29769228#29769228