chore: update CODEOWNERS (#869)

#### Motivation

Allows linz/imagery to review PRs for any aerial imagery related
configuration changes. This was previously in-place but recent
configuration changes meant individual aerial imagery tilesets could no
longer be reviewed by linz/imagery.

#### Modification

Allows data managers to review PRs that related to their data domain.

.github/CODEOWNERS

@@ -1,3 +1,5 @@
 * @linz/proj-basemaps-dev
+config/tileset/*/*.json @linz/proj-basemaps-dev @linz/imagery
 config/tileset/aerial.json @linz/proj-basemaps-dev @linz/imagery
 config/tileset/event.*.json @linz/proj-basemaps-dev @linz/imagery
+config/tileset/scanned.*.json @linz/proj-basemaps-dev @linz/imagery