geopose+json should be geoposejson, as it was previously a duplicate.

Previously, both application/geopose+json and application/geo+json would have the geojson extension.

From the README:

Test at build time that there are no duplicated media types in mime.types.

It seems duplicated media types aren't desired.

This has also been causing lighttpd autopkgtests to fail with:

255s Duplicate mimetype: '.geojson' => 'application/geopose+json' (already have 'application/geo+json'), merging to 'application/octet-stream'