The documentation mentiones the '--update' flag for 'regolith install…

…-all' command.

docs/docs/guide/installing-filters.md

@@ -104,6 +104,12 @@ regolith install name_ninja --update
 
 Alternatively, you can modify the `version` field in `config.json` and run `regolith install-all`. Regolith install-all is useful for working in a team, when other team members may have to update or add filters to the project.
 
+If you want to update all filters in your project, you can use the `--update` flag with the `install-all` command.
+
+```
+regolith install-all --update
+```
+
 ### Updating resolvers
 
 When using short names for filters, Regolith uses a resolver file from a remote repository to determine the URL of the filter.