Examples don't work due to goerli stream being deprecated

[9oelM]

I know we talked on Discord, but just putting it here for better tracking.

Describe the bug

Goerli stream is deprecated, so it needs to be changed to sepolia stream.

All places that use goerli.starknet.a5a.ch shouldn't work

To Reproduce

Try the example at https://github.com/apibara/dna/tree/main/examples/postgres

Expected behavior

The example should work.

Additional context

Add any other context about the problem here.

[fracek]

I cleaned up the examples from the repo and will move them to the documentation.