Update PUWG Charter: meeting schedule

Moved to correct project

Created merge request for review

The meetings time and place are not something that should be in a charter. It is not a governance decision. A charter is define the groups objectives, structure, governance and other 'high-level' information. And meeting times and places needs to be flexible and change according to the members at the time, or any special circumstances. I suggest changing the text to indicate that the details of the meeting are announced on the PUWG project page.