Create a new PDF as a Buffer + Upgrade to Muhammara 3.0.0

[deltazero-cz]

Hi, I often use PDFs as buffers instead of sync fs files. I've made some small updates in order to be able to create new PDF using buffers (both isBufferSrc and isNewPDF are true). Use as follows:

const buffer = new HummusRecipe(Buffer.from('new'), null, {
    version: 1.6,
    author: 'John Doe',
    title: 'Hummus Recipe',
    subject: 'A brand new PDF'
})
    .createPage('letter-size')
    .endPage()
    .endPDF(); // no callback -> returns a buffer

[julianhille]

hey there, im the maintainer of muhammara and started implementing recipe directly into muhammara, it would be awesome to get some feedback on this: julianhille/MuhammaraJS#253

[chunyenHuang]

Thanks can you help with this PR too #234

I haven't worked for this repo for a while. I am thinking maybe I can add you guys to the admin to merge codes as needed.
I will setup the npm workflow to deploy programmatically once merged.