The error reports a magic number issue.
I suspect the previous code was working because of typo in "Content-Type" ("Content-type") header that was ignoring the header. But the header has been fixed with https://github.com/eblondel/geosapi/commit/8aa7c006e4b8cb37083f4b2f150795f86d74ee82 breaking the upload of shapefile where a empty Content-Type was set.
The error reports a magic number issue. I suspect the previous code was working because of typo in "Content-Type" ("Content-type") header that was ignoring the header. But the header has been fixed with https://github.com/eblondel/geosapi/commit/8aa7c006e4b8cb37083f4b2f150795f86d74ee82 breaking the upload of shapefile where a empty Content-Type was set.