fix(subproviders/filters): Rename class from SubscriptionsSubprovider to FiltersSubprovider

subproviders/filters.js

@@ -1,12 +1,12 @@
 const ProviderSubprovider = require('./json-rpc-engine-middleware')
 const createFilterMiddleware = require('eth-json-rpc-filters')
 
-class SubscriptionsSubprovider extends ProviderSubprovider {
+class FiltersSubprovider extends ProviderSubprovider {
   constructor() {
-    super(({ blockTracker, provider, engine }) => {
+    super(({ blockTracker, provider }) => {
       return createFilterMiddleware({ blockTracker, provider })
     })
   }
 }
 
-module.exports = SubscriptionsSubprovider
+module.exports = FiltersSubprovider