r12b has been forever the default. Let's explicitly request that version
where we know we need it.

Note; there's other builds that still implicitly rely on that version
that don't use the buildjni flag. We don't really have a good way of
finding those, except manually.

!5262

```bash
for f in `grep --files-with-matches 'Auto Update Mode:None' metadata/*.txt |sed 's,^metadata/\(.*\)\.txt$,\1,'`; do echo $f; done >  /tmp/rewrite
fdroid rewritemeta --to yml `cat /tmp/rewrite`
for f in `cat /tmp/rewrite`; do git rm -f metadata/${f}.txt; git add metadata/${f}.yml; done
```