Add requires.tables to <layer>.yaml (#1236)

**NOTE** this can only be merged after the next tools version is released.

Added required Postgres tables to the `<layer>.yaml` definition.
Close: #1220

PR of tools: https://github.com/openmaptiles/openmaptiles-tools/pull/370

layers/water_name/water_name.yaml

@@ -1,5 +1,9 @@
 layer:
   id: "water_name"
+  requires:
+    tables:
+      - ne_10m_geography_marine_polys
+      - lake_centerline
   description: |
       Lake center lines for labelling lake bodies.
       This is based of the [osm-lakelines](https://github.com/lukasmartinelli/osm-lakelines) project