Bibtex type `misc` does not require author

[Michael Aye]

The Bibtex entry type "misc" has no required fields (https://en.wikipedia.org/wiki/BibTeX#Entry_types) but bibm refuses to take this bibtex file:

@MISC{Nasa_undated-bs,
  title  = "{NASA} {SMD} Annual Report 2018",
  author = "{NASA}"
}

$ bibm merge test.bib                                                                        (py37)
Traceback (most recent call last):
  File "/Users/klay6683/miniconda3/envs/py37/bin/bibm", line 10, in <module>
    sys.exit(main())
  File "/Users/klay6683/miniconda3/envs/py37/lib/python3.7/site-packages/bibmanager/__main__.py", line 748, in main
    args.func(args)
  File "/Users/klay6683/miniconda3/envs/py37/lib/python3.7/site-packages/bibmanager/__main__.py", line 83, in cli_merge
    bm.merge(bibfile=args.bibfile, take=args.take)
  File "/Users/klay6683/miniconda3/envs/py37/lib/python3.7/site-packages/bibmanager/bib_manager/bib_manager.py", line 623, in merge
    new = loadfile(bibfile)
  File "/Users/klay6683/miniconda3/envs/py37/lib/python3.7/site-packages/bibmanager/bib_manager/bib_manager.py", line 499, in loadfile
    bibs = [Bib(entry) for entry in entries]
  File "/Users/klay6683/miniconda3/envs/py37/lib/python3.7/site-packages/bibmanager/bib_manager/bib_manager.py", line 499, in <listcomp>
    bibs = [Bib(entry) for entry in entries]
  File "/Users/klay6683/miniconda3/envs/py37/lib/python3.7/site-packages/bibmanager/bib_manager/bib_manager.py", line 133, in __init__
    raise ValueError(f"Bibtex entry '{self.key}' is missing author, "
ValueError: Bibtex entry 'Nasa_undated-bs' is missing author, title, or year.

Note, i'm not saying this is a good bibtex entry, as obviously that NASA report has authors, years etc. But formally speaking bibm shouldn't reject this entry, as it's defined by BibTex to not require any field. Of course bibm could decide that @misc entries are out of scope for itself.

[Patricio Cubillos]

Right. I'm going to keep this type of entries out of the scope of bibmanager (at least until somebody comes with a reasonable case needing to use a 'misc' entry for a peer-review article).
Thanks.

[Michael Aye]

But, then you need to implement a stable response to it, b/c ppl will have @misc entries. Your import should not fail, but should simply ignore @misc and tell the user so.

[Patricio Cubillos]

Reopening this issue, since this is basically the same as #78 (which will be taken care very very soon to allow entries without titles, authors, or year).