Evaluation & migration guide for existing 3.0-potel customers

[dingsdax]

by the time we release the first version, find a way to contact existing customers and/or ship a new alpha with a deprecation warning

[linear]

PY-1898

[sentrivana]

• Added an announcement: v3.0 is dead, long live v3.0! #4955
• Working on the last alpha with the warning: Add warning about 3.0 #4956

[sentrivana]

• Added a helpdesk page: https://sentry.zendesk.com/hc/en-us/articles/42382711364379--Python-SDK-What-Is-the-Status-of-Python-SDK-Version-3-0
• We have quite some orgs (200+) sending events from a 3.0 alpha: https://sentryio.cloud.looker.com/dashboards/1849?SDK+Family=Python&SDK+Version=3.0.0%25&SDK+Major%2FMinor+Version=3.0.X&Organization+ID=not+1
• Checking with support folks if we can reach out ^

[sentrivana]

Will close. We made comms publicly accessible, but we'll not reach out to every org separately as we've made the decision to port most public facing changes onto the "new" 3.0 — so there will be continuity between the current alphas and the new prereleases, once they're out.