Update checks.md "Summary Table" doc (#1522)

The clomonitor_name field is mandatory to map entries in the landscape to the CLOMonitor data files. Without it, checks based on the landscape cannot be performed. This PR updated the doc accordingly, see #1519

Signed-off-by: Yacine Kheddache <[email protected]>

Author: yada

docs/checks.md

@@ -296,6 +296,14 @@ This check passes if:
 
 - At least *one* of the [summary_* fields](https://github.com/cncf/landscape/blob/master/docs/item_summary.md) has been set in the project's *extra* section in the [Landscape yaml file](https://github.com/cncf/landscape/blob/master/landscape.yml).
 
+Please note that the clomonitor_name field is **mandatory** for this check to pass:
+```sh
+extra:
+clomonitor_name: project-name
+```
+
+The project-name used in the clomonitor_name field must match exactly the project's name used in the corresponding CLOMonitor [data file](https://github.com/cncf/landscape2/blob/e45368319bf44b5894039f6b49c6468bdff67112/docs/config/data.yml#L140-L144).
+
 ### Website
 
 **ID**: `website`