Error on startup on Linux

OS: Pop!_OS 18.10 (Ubuntu 18.10)
Node: v10.14.2

```sh
$ npm start

> choo-electron@1.0.0 start /home/aral/ind.ie/hypha/spikes/choo-electron
> cross-env NODE_ENV=development electron main.js

App threw an error during load
TypeError: app.makeSingleInstance is not a function
at Object. (/home/aral/ind.ie/hypha/spikes/choo-electron/main.js:21:22)
at Object. (/home/aral/ind.ie/hypha/spikes/choo-electron/main.js:66:3)
at Module._compile (internal/modules/cjs/loader.js:693:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:704:10)
at Module.load (internal/modules/cjs/loader.js:602:32)
at tryModuleLoad (internal/modules/cjs/loader.js:541:12)
at Function.Module._load (internal/modules/cjs/loader.js:533:3)
at loadApplicationPackage (/home/aral/ind.ie/hypha/spikes/choo-electron/node_modules/electron/dist/resources/default_app.asar/main.js:119:12)
at Object. (/home/aral/ind.ie/hypha/spikes/choo-electron/node_modules/electron/dist/resources/default_app.asar/main.js:164:5)
at Object. (/home/aral/ind.ie/hypha/spikes/choo-electron/node_modules/electron/dist/resources/default_app.asar/main.js:204:3)
A JavaScript error occurred in the main process
Uncaught Exception:
TypeError: app.makeSingleInstance is not a function
at Object. (/home/aral/ind.ie/hypha/spikes/choo-electron/main.js:21:22)
at Object. (/home/aral/ind.ie/hypha/spikes/choo-electron/main.js:66:3)
at Module._compile (internal/modules/cjs/loader.js:693:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:704:10)
at Module.load (internal/modules/cjs/loader.js:602:32)
at tryModuleLoad (internal/modules/cjs/loader.js:541:12)
at Function.Module._load (internal/modules/cjs/loader.js:533:3)
at loadApplicationPackage (/home/aral/ind.ie/hypha/spikes/choo-electron/node_modules/electron/dist/resources/default_app.asar/main.js:119:12)
at Object. (/home/aral/ind.ie/hypha/spikes/choo-electron/node_modules/electron/dist/resources/default_app.asar/main.js:164:5)
at Object. (/home/aral/ind.ie/hypha/spikes/choo-electron/node_modules/electron/dist/resources/default_app.asar/main.js:204:3)
```