rez-bind os requires arch

[cfxegbert]

When running rez-bind os the resulting package.py includes a requirement on arch-amd64. A operating system can run on multiple architectures. The requirement on arch should be relaxed.

Environment

• windows-10.0.19044.SP0
• rez 3.1.0
• Rez python version 3.10.10

To Reproduce

1. My rezconfig.py contains the following mapping

   platform_map = {
       "os": {
           r"(osx|windows)-(\d+)\..*": r"\1-\2",
       },
       "arch": {"AMD64": "amd64"},
   }

2. rez-bind os

Expected behavior In the os/windows-10/package.py

requires = [
    'platform-windows'
]

Actual behavior In the os/windows-10/package.py

requires = [
    'platform-windows',
    'arch-amd64'
]