Compress all wheel content with explicit ZIP_DEFLATED (#715) (#838)

https://docs.python.org/2/library/zipfile.html#zipfile.ZipFile.writestr

Note: When passing a ZipInfo instance as the zinfo_or_arcname parameter,
the compression method used will be that specified in the compress_type
member of the given ZipInfo instance. By default, the ZipInfo
constructor sets this member to ZIP_STORED.

poetry/masonry/builders/wheel.py

@@ -259,7 +259,7 @@ def _add_file(self, wheel, full_path, rel_path):
                 hashsum.update(buf)
 
             src.seek(0)
-            wheel.writestr(zinfo, src.read())
+            wheel.writestr(zinfo, src.read(), compress_type=zipfile.ZIP_DEFLATED)
 
         size = os.stat(full_path).st_size
         hash_digest = urlsafe_b64encode(hashsum.digest()).decode("ascii").rstrip("=")