I missed it in the release notes, but there's a breaking change in the ota component in ESPHome 2024.6.0. I figured I'd save folks some time and share the fix here.

If your OTA config looks like this;

...

ota:
  password: "*************"
  num_tries: 3
  safe_mode: on

...

Now you'll need to add a platform key to start a list, and either comment out the other option or move them to a new component.

...

ota:
  - platform: esphome
    password: "*************"
  #num_tries: 3
  #safe_mode: on

...

edit: Here's the PR introducing this change https://github.com/esphome/esphome/pull/6459