Deepen English Channel to 120m

From Xylar: Wikipedia says the average depth at it's widest point is 120
m. That seems like as good a number as any. The deepest point is 180 m
deep while other parts are quite a bit shallower (45 m) so 120 m would
be a reasonable compromise.

ocean/transect/English_Channel_Deepen/transect.geojson

@@ -9,7 +9,7 @@
                 "object": "transect",
                 "component": "ocean",
                 "author": "Mark Petersen",
-                "depth": "15.0"
+                "depth": "120.0"
             },
             "geometry": {
                 "type": "LineString",