Importing fails with Python 3.9

[here-abarany]

Describe the bug
Python 3.9 removed the "encoding" parameter for json.loads(), leading to an unexpected keyword argument exception being thrown when attempting to load a glTF file.

To Reproduce
Steps to reproduce the behavior:

1. Launch Blender with a system using Python 3.9.
2. Import a glTF or glb file.

Expected behavior
File imports without error.

Screenshots

Version

• OS: Arch Linux
• Blender Version 2.91

Additional context
Removing the encoding parameter in gltf_io_gltf.py line 64 fixes the issue.

[julienduroure]

Hello,
Blender is bundled with its own python interpreter, that is the only python version that is officially supported.
For 2.91, this is 3.7.7

[scurest]

From the 3.7 docs

The other arguments have the same meaning as in load(), except encoding which is ignored and deprecated.

encoding has been ignored since 3.1, so it should be deleted even in 3.7.

I only put the encoding= arg in in #1238 because I thought incorrectly that json.loads(str(json_bytes, encoding='utf-8')) was the same as json.loads(json_bytes, encoding='utf-8').

[makidoll]

I'm having this issue as well using Arch Linux with Python 3.9.1. I had to manually remove all encoding='utf8' in the plugin to get it to work for now.