home-assistant: pin aioesphomeapi to 7.0.0

[CRTified]

Motivation for this change

Version of Home Assistant in nixpkgs is incompatible with aioesphomeapi-8.0.0, so this PR pins the version.
Mandatory to be able to use e.g. lights, otherwise Home Assistant fails with:

ERROR (MainThread) [homeassistant.setup] Unable to prepare setup for platform esphome.light: Platform not found (cannot import name 'LightColorMode' from 'aioesphomeapi' (/nix/store/yw40d736xvv7criyfffz88pcfnvvavx0-python3.9-aioesphomeapi-8.0.0/lib/python3.9/site-packages/aioesphomeapi/__init__.py)).

Relevant comment in the bump of aioesphomeapi:
#135669 (comment)

Things done

Added it manually via packageOverrides on the services.home-assistant.package option (so I didn't test the PR in exaclty this form, but an equivalent override).

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• 21.11 Release Notes (or backporting 21.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[CRTified]

ping @mweinelt - asked me to create this PR

[fabaff]

I didn't check #135669 properly. 8.0.0 should have go with 2021.9.0 not before.

[CRTified]

Feel free to close this PR in case aioesphomeapi gets reverted.