Update @actions/cache to 5.1.0 and add security overrides for undici and fast-xml-parser (#1579)

* Update @actions/cache to 5.1.0, add security overrides for undici and fast-xml-parser, update licenses

* Fix debug message for unchanged cache validation in tests

* Fix formatting in cache validation test for unchanged cache

* Bump version to 6.5.0

src/cache-save.ts

@@ -62,7 +62,11 @@ const cachePackages = async (packageManager: string) => {
   }
 
   const cacheId = await cache.saveCache(cachePaths, primaryKey);
-  if (cacheId == -1) {
+  if (cacheId === -1) {
+    // saveCache returns -1 without throwing when the cache was not saved, e.g.
+    // a reserve collision or a read-only token (fork PR). @actions/cache has
+    // already logged the reason at the appropriate severity, so just trace it.
+    core.debug(`Cache was not saved for the key: ${primaryKey}`);
     return;
   }