fix: pin highlight.js script and theme with SRI

Author: clean6378-max-it

templates/base.html

@@ -16,8 +16,12 @@
   </script>
   <link rel="stylesheet" href="/static/css/style.css">
   <!-- Highlight.js for code syntax highlighting -->
-  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/vs2015.min.css" id="hljs-theme">
-  <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/highlight.min.js"></script>
+  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/vs2015.min.css" id="hljs-theme"
+    integrity="sha512-mtXspRdOWHCYp+f4c7CkWGYPPRAhq9X+xCvJMUBVAb6pqA4U8pxhT3RWT3LP3bKbiolYL2CkL1bSKZZO4eeTew=="
+    crossorigin="anonymous">
+  <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/highlight.min.js"
+    integrity="sha512-D9gUyxqja7hBtkWpPWGt9gfbfaMGVt9gnyCvYa+jojwwPHLCzUm5i8rpk7vD7wNee9bA35eYIjobYPaQuKS1MQ=="
+    crossorigin="anonymous"></script>
   <!-- Marked.js for Markdown rendering -->
   <script src="https://cdnjs.cloudflare.com/ajax/libs/marked/12.0.1/marked.min.js"
     integrity="sha384-3zf4Pen4fXU90jGg3cxmo7BF4dq8HMtF2s07c/Hhd1Fh+Encm6ApPvNm8vrMJbWu"