Describe the bug
PyPy 7.3.4 doesn't work on Windows, likely because the action is trying to install the 32-bit version (which does not exist) even when 64-bit is specified (which does exist).

Which version of the action are you using?

• v1
• v2
• Some other tag (such as v2.0.1 or master)

Environment

• self-hosted
• Linux
• Windows
• Mac

Python Versions
pypy-3.7-v7.3.4, pypy-3.7-v7.3.4rc1, pypy-3.7-v7.3.4rc2

To Reproduce

    strategy:
      matrix:
        architecture: ["x86", "x64"]
    steps:
    - uses: actions/setup-python@v2
      with:
        python-version: pypy-3.7-v7.3.4rc1
        architecture: ${{ matrix.architecture }}

Gives the following error for both architectures:

Run actions/setup-python@v2
  with:
    python-version: pypy-3.7-v7.3.4rc1
    architecture: x64
    token: ***
PyPy version 3.7 (v7.3.4-rc.1) was not found in the local cache
Error: PyPy version 3.7 (v7.3.4-rc.1) with arch x86 not found

Run/Repo Url
https://github.com/nulano/Pillow/runs/2235978354?check_suite_focus=true

Additional context
This is likely caused by the fact this action assumes PyPy is 32-bit only on Windows, while in reality starting with version 7.3.4 PyPy is 64-bit only on Windows.
Related to #168 (comment)