bump pnpm => 8.15.3 (#2248)

## Checklist

- [-] I have added
[tests](https://www.cursorless.org/docs/contributing/test-case-recorder/)
- [-] I have updated the
[docs](https://github.com/cursorless-dev/cursorless/tree/main/docs) and
[cheatsheet](https://github.com/cursorless-dev/cursorless/tree/main/cursorless-talon/src/cheatsheet)
- [-] I have not broken the cheatsheet

Author: pokey

package.json

@@ -62,6 +62,6 @@
   "engines": {
     "node": ">=18.18.2"
   },
-  "packageManager": "pnpm@8.12.0",
+  "packageManager": "pnpm@8.15.3",
   "type": "module"
 }