docs: Fix broken link in Volley training am: 05dd9d2c29 am: 346114e346
am: c8c2abed0e

* commit 'c8c2abed0e7418d7e0fb0ef73a0c363cec011b95':
  docs: Fix broken link in Volley training

Change-Id: I916717fca33fc1466cd1c022c6a4f5f931d00ebe