Update test_network.md

[jannesklee]

Change version at the beginning of the tutorial, because old version numbers lead to abortion in following steps.

Type of change

• Documentation update

[denyeart]

Thanks for the update. We can merge this one, but I think ultimately we should remove the version reference in this doc and simply point to the main install doc page, like we've done in later release branches and main.

Please sign the commit using the instructions at: https://github.com/hyperledger/fabric/pull/3204/checks?check_run_id=4996692476

[denyeart]

No response from PR creator, closing...