change glottocode for Dadu'a to dadu1237

[Bibiko]

https://github.com/lexibank/abvd/blob/master/cldf/languages.csv#L2861

There are maybe still discussions about the classification of Dadu'a but since Glottolog has a code for it, it would be better to use it. So far Dadu'a is probably very likely Wetarese.

see:

• https://iso639-3.sil.org/sites/iso639-3/files/change_requests/2019/2019-053.pdf
• Taylor-Leech 2009 'The language situation in Timor-Leste'
• Taylor-Leech 2007 'The Ecology of Language Planning in Timor-Leste: A Study of Language Policy, Planning and Practices in Identity Construction'
  and others

https://glottolog.org/resource/languoid/id/dadu1237

[SimonGreenhill]

thanks Hans -- updated.