v2.18.0

This is a major update that brings in Erlang/OTP 26, Buildroot 2023.02.2 and
Linux 5.10.162.

• New features

  • CA certificates are included for OTP 26.

• Updated dependencies

  • nerves_system_br v1.23.1
  • Buildroot 2023.02.2
  • Erlang/OTP 26.0.2
  • Linux 5.10.162