[AIRFLOW-6781] Enforce example_dags and guide for Google integrations

[mik-laj]

Hello,

For operators from the Google package we have examples of DAGs and guides for the majority of integrations. Ther existence is already common, so we can enforce this rule for future integrations also.

Best regards,

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Issue link: AIRFLOW-6781

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[codecov-io]

Codecov Report

Merging #7404 into master will decrease coverage by 0.27%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #7404      +/-   ##
==========================================
- Coverage   86.61%   86.33%   -0.28%     
==========================================
  Files         873      874       +1     
  Lines       40757    40868     +111     
==========================================
- Hits        35300    35284      -16     
- Misses       5457     5584     +127

Impacted Files	Coverage Δ
airflow/kubernetes/volume_mount.py	44.44% <0%> (-55.56%)	⬇️
airflow/kubernetes/volume.py	52.94% <0%> (-47.06%)	⬇️
airflow/kubernetes/pod_launcher.py	47.18% <0%> (-45.08%)	⬇️
...viders/cncf/kubernetes/operators/kubernetes_pod.py	69.38% <0%> (-25.52%)	⬇️
airflow/kubernetes/refresh_config.py	50.98% <0%> (-23.53%)	⬇️
airflow/config_templates/airflow_local_settings.py	65.38% <0%> (-6.36%)	⬇️
airflow/utils/log/stackdriver_task_handler.py	97.14% <0%> (ø)

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[potiuk]

Suggested change

	MISSING_EXAMPLED_DAG = {
	MISSING_EXAMPLE_DAG = {

[mik-laj]

Fixed.