pwa plugin: allow to define cacheId to prevent 'not allowed error'

[mutefiRe]

What problem does this feature solve?

I'm having trouble with the pwa plugin for 3.0. I want to use InjectManifest, but building the project doesn't work because cacheId is not allowed for workbox 3 in InjectManifest Mode. But cacheId is always set by cli-plugin-pwa/index.js, no matter which mode is set.
Error message: ERROR ValidationError: "cacheId" is not a supported parameter.

What does the proposed API look like?

Allow setting CacheId in vue.config.js and also add the possibilty to use null as value, which causes cli-plugin-pwa/index.js to remove the attribute, to prevent this error.

[umarov]

I stumbled upon this issue as well and submitted a PR #939.

[mutefiRe]

Very nice, thanks 😉