Fix link for 'getting-started-python' repo. (#7498)
Fix link for 'getting-started-python' repo. (#7498)

Closes #7488.
tseaver/google-cloud-python,tswast/google-cloud-python,tseaver/google-cloud-python,GoogleCloudPlatform/gcloud-python,GoogleCloudPlatform/gcloud-python,googleapis/google-cloud-python,tswast/google-cloud-python,googleapis/google-cloud-python,tseaver/google-cloud-python,tswast/google-cloud-python