Pip install is failing for unit tests on windows

[vfdev-5]

🐛 Bug description

Collecting pip
  Downloading pip-21.3-py3-none-any.whl (1.7 MB)
Installing collected packages: pip
  Attempting uninstall: pip
    Found existing installation: pip 21.2.4
    Uninstalling pip-21.2.4:
      Successfully uninstalled pip-21.2.4
ERROR: Could not install packages due to an OSError: [WinError 5] Access is denied: 'C:\\hostedtoolcache\\windows\\Python\\3.8.10\\x64\\~cripts\\pip.exe'
Consider using the `--user` option or check the permissions.

• https://github.com/pytorch/ignite/pull/2241/checks?check_run_id=3890679130

We would like to fix the CI here:

ignite/.github/workflows/unit-tests.yml

Lines 57 to 61 in 0be46fd

	- name: Get pip cache dir
	id: pip-cache
	run: |
	pip install -U pip
	echo "::set-output name=dir::$(pip cache dir)"

[trsvchn]

Again very weird.. this issue starts to pop up recently