Add email to author data for 1.2.0 and CodeMeta output

[sdruskat]

This PR aims to fix #285.

It adds emails to authors for

• CFF 1.2.x
• CFF 1.1.x
• CFF 1.0.x

and output formats

• CodeMeta
• schema.org

As these are the only 2 formats including email information for authors, this can be assumed to be a complete fix for the issue.

[sdruskat]

Hi @jspaaks, this is good to review now.
As for the CI failures: 3.6 isn't supported anymore I think, and 3.9 linting shows the same issues as in #281. I'll try to fix this in another PR.

[apirogov]

Will this eventually be merged? Just ran into problems with codemetapy just picking up email, and cffconvert just picking up orcid for the codemeta, and with the inability of codemetapy to merge, leading to information loss.

If this is merged, the workaround would be simplified to just prioritizing the codemeta output produced by cffconvert.

[jspaaks]

'______E' should still be added

[jspaaks]

FYI I'm expanding on this in PR

• More work on email in schema and codemeta #309

[jspaaks]

Hi Stephan, thanks for your work on this. I'm merging this, and building on top of it in PR #309 FYI