fixup: properly read gzipped content from S3

We did not find a native way to do this from django-storages API.

umap/storage.py

@@ -2,6 +2,7 @@
 import os
 import shutil
 import time
+from gzip import GzipFile
 from pathlib import Path
 
 from botocore.exceptions import ClientError
@@ -106,7 +107,7 @@ def get_version(self, ref, instance):
             )
         except ClientError:
             raise ValueError(f"Invalid version reference: {ref}")
-        return data["Body"].read()
+        return GzipFile(mode="r", fileobj=data["Body"]).read()
 
     def get_version_path(self, ref, instance):
         return self.url(instance.geojson.name, parameters={"VersionId": ref})

umap/tests/test_datalayer_s3.py

@@ -80,7 +80,7 @@ def test_update_should_add_version(map, datalayer):
 
 def test_get_version(map, datalayer):
     assert len(datalayer.versions) == 1
-    datalayer.geojson = ContentFile('{"foo": "bar"}', "foo.json")
+    datalayer.geojson = ContentFile(b'{"foo": "bar"}', "foo.json")
     datalayer.save()
     assert len(datalayer.versions) == 2
     latest = datalayer.versions[0]["ref"]