refactor: update imports to use ES module syntax and improve test structure (#1350)

- Changed import statements across multiple files to use the .js extension for ES module compatibility.
- Refactored test files to utilize jest's unstable_mockModule for mocking core actions.
- Removed unnecessary spy instances in tests, replacing them with direct mocked function calls.
- Updated TypeScript configuration to target ES2022 and use NodeNext module resolution.
- Removed the tsconfig.spec.json file and adjusted the main tsconfig.json to exclude test files.

src/interfaces/comment.ts

@@ -1,4 +1,4 @@
-import {IUser} from './user';
+import {IUser} from './user.js';
 
 export interface IComment {
   user: IUser | null;

src/interfaces/issue-event.ts

@@ -1,4 +1,4 @@
-import {ILabel} from './label';
+import {ILabel} from './label.js';
 
 export interface IIssueEvent {
   created_at: string;

src/interfaces/issue.ts

@@ -1,7 +1,7 @@
-import {IsoDateString} from '../types/iso-date-string';
-import {Assignee} from './assignee';
-import {ILabel} from './label';
-import {IMilestone} from './milestone';
+import {IsoDateString} from '../types/iso-date-string.js';
+import {Assignee} from './assignee.js';
+import {ILabel} from './label.js';
+import {IMilestone} from './milestone.js';
 import {components} from '@octokit/openapi-types';
 export interface IIssue {
   title: string;

src/interfaces/issues-processor-options.ts

@@ -1,4 +1,4 @@
-import {IsoOrRfcDateString} from '../types/iso-or-rfc-date-string';
+import {IsoOrRfcDateString} from '../types/iso-or-rfc-date-string.js';
 
 export interface IIssuesProcessorOptions {
   repoToken: string;

src/interfaces/state/state.ts

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