fix mqtt logic if no MQTT_HOST is defined #112

	name: PlatformIO CI

	on:
	push:
	branches: [ "main" ]
	pull_request:
	branches: [ "main" ]
	workflow_dispatch: # allow manually calling the action

	jobs:
	build:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	- name: Cache pip
	uses: actions/cache@v3
	with:
	path: ~/.cache/pip
	key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
	restore-keys: \|
	${{ runner.os }}-pip-
	- name: Cache PlatformIO
	uses: actions/cache@v3
	with:
	path: ~/.platformio
	key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}
	- name: Set up Python
	uses: actions/setup-python@v4
	with:
	python-version: '3.10'
	- name: Install PlatformIO
	run: \|
	python -m pip install --upgrade pip
	pip install --upgrade platformio
	- name: Install PlatformIO Libs
	run: pio pkg install
	- name: Use example config
	run: cp src/config_example.h src/config.h
	- name: Run PlatformIO Tests
	# empty target to prevent upload
	run: pio test -e native
	- name: Run PlatformIO
	# empty target to prevent upload
	run: pio run -t ''

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