Set Capella fork epoch for Goerli (#4044)

## Issue Addressed

NA

## Proposed Changes

Sets the Capella fork epoch as per eth-clients/goerli#160.

The fork will occur at:

- Epoch: 162304
- Slot: 5193728
- UTC: 14/03/2023, 10:25:36 pm

## Additional Info

- [x] Blocked on eth-clients/goerli#160 being merged

common/eth2_network_config/built_in_network_configs/prater/config.yaml

@@ -35,8 +35,11 @@ ALTAIR_FORK_EPOCH: 36660
 # Merge
 BELLATRIX_FORK_VERSION: 0x02001020
 BELLATRIX_FORK_EPOCH: 112260
+# Capella
+CAPELLA_FORK_VERSION: 0x03001020
+CAPELLA_FORK_EPOCH: 162304
 # Sharding
-SHARDING_FORK_VERSION: 0x03001020
+SHARDING_FORK_VERSION: 0x04001020
 SHARDING_FORK_EPOCH: 18446744073709551615
 
 # TBD, 2**32 is a placeholder. Merge transition approach is in active R&D.