exporters.md: Add openweathermap_exporter
exporters.md: Add openweathermap_exporter
prometheus/docs,tcolgate/docs,Cepave/openfalcon.io,chosenken/docs,open-falcon/open-falcon.github.io,prometheus/docs,prometheus/docs,tcolgate/docs,chosenken/docs,du2016/prometheus-docs,vic3lord/docs,vic3lord/docs,tcolgate/docs,pdbogen/docs,open-falcon/open-falcon.github.io,du2016/prometheus-docs,ddfreyne/prometheus-docs,du2016/prometheus-docs,ddfreyne/prometheus-docs,Cepave/openfalcon.io,vic3lord/docs,chosenken/docs,Cepave/openfalcon.io,chosenken/docs,pdbogen/docs,open-falcon/open-falcon.github.io,ddfreyne/prometheus-docs,ddfreyne/prometheus-docs,pdbogen/docs