refactor: cdn.jsdelivr.net -> local

src/main/resources/templates/index.html

@@ -23,8 +23,8 @@
 			<button type="button" id="copy" style="width:100px;" data-clipboard-action="copy" data-clipboard-target="#short">Copy</button>
 		</div>
 	</div>
-	<script src="https://cdn.jsdelivr.net/npm/jquery@3.5.1/dist/jquery.min.js"></script>
-	<script src="https://cdn.jsdelivr.net/npm/clipboard@2.0.8/dist/clipboard.min.js"></script>
+	<script src="/js/jquery.min.js"></script>
+	<script src="/js/clipboard.min.js"></script>
 	<script>
 		$('#generate').click(() => {
 			let longURL = $('#long').val();