added warning to waveshare 2.90inv2 inch display

[bzzbzzz]

Description:

Added a warning to the 2.9 inch display because the board rev 2.1 version seems not to work without adding full_update_every: 1 currently (which also means that partial refresh is not supported). Someone opened an issue some time before which is still open.

Related issue: warns about esphome/issues#2334 / esphome/issues#2459

Pull request in esphome with YAML changes: hopefully obsolete with eventual merging of esphome/esphome#2912

Checklist:

• [ ] Branch: next is for changes and new documentation that will go public with the next ESPHome release. Fixes, changes and adjustments for the current release should be created against current.
• [ ] Link added in /index.rst when creating new documents for new components or cookbook.

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[github-actions[bot]]

There hasn't been any activity on this pull request recently. This pull request has been automatically marked as stale because of that and will be closed if no further activity occurs within 7 days. Thank you for your contributions.