[CHORE](docs) fix dead docs link in PRojection README

Signed-off-by: John McCall <john@overturemaps.org>

Author: lowlydba

.github/actions/overture-projection/README.md

@@ -136,7 +136,7 @@ Only skills with `surfaces: [pr-reviewer]` (or no `surfaces` field) are loaded.
 - All other `pr-reviewer` skills are passed to the selection model with their `description`; the model picks which are relevant to the PR.
 - `context-files` are fetched after selection, so only selected skills pay the network cost.
 
-For full frontmatter field reference and authoring guidance see the [omf-devex README](../../../../README.md#skills).
+For full frontmatter field reference and authoring guidance see the [omf-devex README](https://github.com/OvertureMaps/omf-devex/blob/main/README.md#skills).
 
 ## Required workflow permissions