Fix a typo in requirements files

and add swh-storage[listener] dep for the sake of completeness while
building the doc.

requirements-swh-dev.txt

@@ -3,7 +3,7 @@
 ../swh-model
 ../swh-objstorage[testing]
 ../swh-scheduler
-../swh-storage[schemadata]
+../swh-storage[schemata,listener]
 ../swh-loader-core
 ../swh-lister
 ../swh-journal

requirements-swh.txt

@@ -3,7 +3,7 @@ swh-core
 swh-model
 swh-objstorage[testing]
 swh-scheduler
-swh-storage[schemadata]
+swh-storage[schemata,listener]
 swh-loader-core
 swh-lister
 swh-journal