notification_examples: Fix yaml error (#819)
notification_examples: Fix yaml error (#819)

Signed-off-by: Sylvain Rabot <220beee1e7109cdd1ee75c5c980de34352cf48ab@abstraction.fr>
chosenken/docs,ddfreyne/prometheus-docs,du2016/prometheus-docs,ddfreyne/prometheus-docs,du2016/prometheus-docs,prometheus/docs,chosenken/docs,ddfreyne/prometheus-docs,du2016/prometheus-docs,prometheus/docs,chosenken/docs,ddfreyne/prometheus-docs,prometheus/docs,chosenken/docs