Spark On K8S 0.6.0

What's Changed

• feat(airflow): add app_id_suffix argument to Airflow operator by @hussein-awala in #41
• dev: add code of conduct to the project by @hussein-awala in #43
• dev: add a security policy to the project by @hussein-awala in #44
• dev: add a contributing doc to the project by @hussein-awala in #45
• dev: setup sponsorship by adding funding.yml file by @hussein-awala in #46
• feat(airflow): try adopt running job in case of unexpected failures by @hussein-awala in #42

Full Changelog: 0.5.2...0.6.0