bump sandbox from 0.28.2 to 0.30.0 and update the net repo

[andy108369]

• [x] bump sandbox from 0.28.0 to 0.30.0
  • [x] example ref https://github.com/akash-network/support/issues/145
  • [x] https://github.com/akash-network/net/pull/577
  • [x] govt prop 5 submitted & voted
  • [x] upgrade the network (validators & rpc)
  • [x] upgrade the clients (akash provider)
• [x] bump the versions in the net GH repo, chain-registry etc
  • [x] https://github.com/akash-network/net/pull/576
  • [x] https://github.com/cosmos/chain-registry/pull/3275

[andy108369]

upgrade complete