style: fix linting

test/e2e/drop.ts

@@ -5,7 +5,7 @@ import * as chaiAsPromised from 'chai-as-promised'
 use(chaiAsPromised)
 
 class SettingsDrop extends Drop {
-  private foo: string = 'FOO'
+  private foo = 'FOO'
   public bar () {
     return 'BAR'
   }

test/integration/drop/drop.ts

@@ -6,7 +6,7 @@ describe('drop/drop', function () {
   before(() => (liquid = new Liquid()))
 
   class CustomDrop extends Drop {
-    private name: string = 'NAME'
+    private name = 'NAME'
     public getName () {
       return 'GET NAME'
     }