Release v1.2.0

This is a mandatory release for all mainnet users for the upcoming Deneb/Cancun fork on Mainnet, at epoch 269568.

Changes

• Add holesky support via the --holesky flag
• Add dencun support and fork configs for mainnet and holesky
• Update types
• Fix deadlock with syncing primary nodes
• Remove hyper crate logging on debug log levels
• Add serialization of newPayload requests
• Fix SYNCING newPayload responses
• Add per-EL jwt tokens (--nodes http://ipaddress:port#jwt-secret=/path/to/jwt)
• Add metrics and recheck endpoints (GET /metrics GET /recheck)
• Improve node timing logging
• Use concurrent requests for syncing nodes

and other, older patches