Upgrade to pnpm 10

This is working toward harmonization with the glimmer-vm monorepo.

Author: ef4

package.json

@@ -393,9 +393,5 @@
       ]
     }
   },
-  "packageManager": "[email protected]",
-  "volta": {
-    "node": "16.20.0",
-    "pnpm": "8.10.0"
-  }
+  "packageManager": "[email protected]"
 }