Allow shortcut without exit code

[bahmutov]

for example, stubExecOnce("command", "output here") without exit code

[bahmutov]

Version 2.3.0 has been published to NPM. The full release note can be found at stub-spawn-once/releases/tag/v2.3.0.

Tip: safely upgrade dependency stub-spawn-once in your project using next-update