Add bmat task dependency to marine LETKF task (#3224)

Adds bmat task dependency to marine LETKF task as the latter requires
the ensemble to be staged, which is what the bmat task does.

Resolves #3222

workflow/rocoto/gfs_tasks.py

@@ -641,10 +641,10 @@ def prepoceanobs(self):
     def marineanlletkf(self):
 
         deps = []
-        dep_dict = {'type': 'metatask', 'name': f'enkfgdas_fcst', 'offset': f"-{timedelta_to_HMS(self._base['interval_gdas'])}"}
-        deps.append(rocoto.add_dependency(dep_dict))
         dep_dict = {'type': 'task', 'name': f'{self.run}_prepoceanobs'}
         deps.append(rocoto.add_dependency(dep_dict))
+        dep_dict = {'type': 'task', 'name': f'{self.run}_marinebmat'}
+        deps.append(rocoto.add_dependency(dep_dict))
         dependencies = rocoto.create_dependency(dep_condition='and', dep=deps)
 
         resources = self.get_resource('marineanlletkf')