Add docs

Signed-off-by: Michel Hollands <michel.hollands@grafana.com>

docs/dev_update_dependencies.md

@@ -0,0 +1,16 @@
+# Update the dependencies
+
+The dependencies are the version of Loki, Mimir, Agent and so on that are included in this chart.
+The current versions can be found in the [Chart.yaml](../charts/meta-monitoring/Chart.yaml) file.
+
+Run this in the charts/meta-monitoring directory after updating a dependency:
+
+```
+helm dependency update meta-monitoring
+```
+
+List the current dependencies:
+
+```
+helm dependency list meta-monitoring
+```