Update major release guidance

[raffenet]

Remove face-to-face meeting requirement for major release approval, and
updating surrounding text. Retain limit of one major release per year.

[raffenet]

Here's my stab at updating the major release guidance. Please give your feedback!
cc: @dsolt

[dsolt]

This looks good to me.

[kathrynmohror]

Please use emoji reactions ON THIS COMMENT to indicate your position on this proposal.

• You do not need to vote on every proposal
• If you have no opinion, don't vote - that is also useful data
• If you've already commented on this issue, please still vote so
  we know your current thoughts
• Not all proposals solve exactly the same problem, so we may end
  up accepting proposals that appear to have some overlap
  This is not a binding majority-rule vote, but it will be a very
  significant input into the corresponding ASC decision.

Here are the meanings for the emojis:

• Hooray or Rocket: I support this so strongly that I
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• Heart: I think this is an ideal solution
• Thumbs up: I'd be happy with this solution
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  If you want to explain in more detail, feel free to add another
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[jjhursey]

PMIx ASC 1Q 2022

• Passed the first vote: 11 yes / 0 no / 0 abstain
• This is eligible for second vote in the 2Q 2022 ASC quarterly meeting

[jjhursey]

PMIx ASC 2Q 2022

• Passed the second vote: 11 yes / 0 no / 0 abstain
• Will be merged into the next release