Align with official release strategy and adjust constraints

[aj-stein-gsa]

This relates to ...

• the FedRAMP OSCAL baselines
• the Guide to OSCAL-based FedRAMP Content
• the FedRAMP SAP OSCAL Template (JSON or XML Format)
• the FedRAMP SAR OSCAL Template (JSON or XML Format)
• the FedRAMP POA&M OSCAL Template (JSON or XML Format)
• the FedRAMP OSCAL Validations

What happened?

During pairing on constraint develop around checking fedramp-version and oscal-version, colleagues reported that the ADR#2 in repo version of our release strategy is not the same as our canonical updated version on the website (at this time from 87a0d60). The latter was after much feedback from the community that the former had significant drawback. This was decided but not aligned, so we now need to align it.

What needs FedRAMP developer review?

• #863
• #866
• GSA/automate.fedramp.gov#104
• GSA/automate.fedramp.gov#114

Relevant log output

No response

How do we replicate this issue?

1. Perform high-level review of this repo and the website.

Where, exactly?

In multiple locations, see below.

Other relevant details

Expected fixes:

• Deprecate ADR2 and/or update it with a backported decision record. #866
• Update the website page with example tags to be actually semver, not fedramp-3.0.0 per example. GSA/automate.fedramp.gov#104
• Update milestones with old version format based on version in this repo.
• Update wiki guidance on versioning in this repo. (Completed in wiki, diff of the change.
• Update recently merged constraint to check for "new" fedramp-version allowed-value correctly.
• Redefine and move work in #618 and #833 accordingly and complete them.