Use cache instead of artifacts

src/interfaces/state/state-storage.ts

@@ -0,0 +1,4 @@
+export interface IStateStorage {
+  save(serializedState: string): Promise<void>;
+  restore(): Promise<string>;
+}

src/interfaces/state/state.ts

@@ -1,4 +1,4 @@
-import {IIssue} from './issue';
+import {IIssue} from '../issue';
 
 export interface IState {
   isIssueProcessed(issue: IIssue): boolean;