set up arduino-CI for the library

[RobTillaart]

Please read - https://github.com/Arduino-CI/arduino_ci/blob/master/REFERENCE.md

• add .github\workflows\arduino_test_runner.yml
• add .arduino-ci.yml
• add test\unit_test_01.cpp_placeholder
• rename above file to .cpp when there is a fix for Dependency problem on AVR specific #include. Arduino-CI/arduino_ci#251

content .arduino-ci.yml

compile:
  # Choosing to run compilation tests on 2 different Arduino platforms
  platforms:
    - uno
    - leonardo
    - due
    - zero
  # Declaring Dependent Arduino Libraries (to be installed via the Arduino Library Manager)
  libraries:
    - "OneWire"

unittest:
  # These dependent libraries will be installed
  libraries:
    - "OneWire"
    # fix the #include "util/crc16" problem here?
    

content arduino_test_runner.yml

---
name: Arduino CI

on: [push, pull_request]

jobs:
  arduino_ci:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2
      - uses: Arduino-CI/action@master
          #   Arduino-CI/[email protected]

Example content unit_test_01.cpp see - https://github.com/RobTillaart/DS18B20_RT/blob/master/test/unit_test_001.cpp_avr_specific

[RobTillaart]

This one is solved as the PR for the build is merged.