Group artifact actions (#28413)

.github/renovate.json5

@@ -99,6 +99,13 @@
       matchUpdateTypes: ['patch', 'minor'],
       groupName: 'eslint (non-major)',
     },
+    {
+      // Group actions/*-artifact in the same PR
+      matchManagers: ['github-actions'],
+      matchPackageNames: ['actions/download-artifact', 'actions/upload-artifact'],
+      matchUpdateTypes: ['major'],
+      groupName: 'artifact actions (major)'
+    },
     {
       // Update @types/* packages every week, with one grouped PR
       matchPackagePrefixes: '@types/',