write_dwc updates

[sannegovaert]

• rename helper functions
  dwc_occurrence_gps > create_gps_occurrence
dwc_occurrence_ref > create_ref_occurrence

fix #70

• Provide no default for directory
• Update example

fix #71

• Write data frame invisibly
• Write meta.xml file
• • Add tests for meta.xml file
• Update output filename(s): to occurrence.csv
• Simplify test helper functions

fix #76

• update title
• update abstract

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.57%. Comparing base (ccdc3e8) to head (d6bdd9f).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #75      +/-   ##
==========================================
- Coverage   87.20%   84.57%   -2.64%     
==========================================
  Files           9        9              
  Lines         508      512       +4     
==========================================
- Hits          443      433      -10     
- Misses         65       79      +14     

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[peterdesmet]

Nice work! I have updated:

• NEWS.md (lots was missing from earlier versions too)
• Don't add [subsampled representation] in write_dwc() (cf write_eml())
• Update write_eml() documentation
• Remove package argument in write_eml(): it is not used and allows to just generate the EML from a provided DOI
• Add optional parameter generated_paragraph to enable/disable the extra paragraph in the abstract
• Have write_eml() return eml invisibly (cf. write_dwc()), allowing easier tests
• Reorganize tests cf. camtrapdp