chore: update tutorial section landing page (#543)

## Description
Update tutorial section landing page to include the dashboard tutorial
...

## Related Issue

Fixes #542
<!-- or -->
Relates to #

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [x] Other (security config, docs update, etc)

## Checklist before merging

- [x] Test, docs, adr added or updated as needed
- [x] [Contributor Guide
Steps](https://github.com/defenseunicorns/pepr/blob/main/CONTRIBUTING.md#submitting-a-pull-request)
followed

docs/040_pepr-tutorials/README.md

@@ -3,3 +3,4 @@
 In this section, we provide tutorials for using Pepr. These tutorials are:
 
 - [Create a Pepr Module](010_create-pepr-module.md)
+- [Create a Pepr Dashboard](020_create-pepr-dashboard.md)