Some terribleness to make updating work on windows

Squirrel doesn't handle the executable changing name, as hopefully
explained in comments

scripts/electron_afterPack.js

@@ -0,0 +1,15 @@
+const fsProm = require('fs').promises;
+const path = require('path');
+
+exports.default = async function(context) {
+    const { electronPlatformName, appOutDir } = context;
+
+    // Squirrel windows will try to relaunch the app using an executable of the same name as
+    // before in the new version, so will fail if the executable is now called something else.
+    // We add a fake Riot.exe that it can run which runs the real one.
+    // This also gets signed automatically, presumably because electron-build just looks for all
+    // exe files and signs them all...
+    if (electronPlatformName === 'win32') {
+        await fsProm.copyFile('build/rebrand_stub/rebrand_stub.exe', path.join(appOutDir, "Riot.exe"));
+    }
+};