artifact: honor Retry-After on HTTP 429 and prepare 6.3.0

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@actions/artifact",
-  "version": "6.2.2",
+  "version": "6.3.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@actions/artifact",
-      "version": "6.2.2",
+      "version": "6.3.0",
       "license": "MIT",
       "dependencies": {
         "@actions/core": "^3.0.1",