v1.1.1 spec updates (#2684)

* update initializing from eth1 for merge genesis

* read execution payload header from file lcli

* add `create-payload-header` command to `lcli`

* fix base fee parsing

* Apply suggestions from code review

* default `execution_payload_header` bool to false when deserializing `meta.yml` in EF tests

Co-authored-by: Paul Hauner <paul@paulhauner.com>

lcli/src/create_payload_header.rs

@@ -0,0 +1,39 @@
+use bls::Hash256;
+use clap::ArgMatches;
+use clap_utils::{parse_optional, parse_required};
+use int_to_bytes::int_to_bytes32;
+use ssz::Encode;
+use std::fs::File;
+use std::io::Write;
+use std::time::{SystemTime, UNIX_EPOCH};
+use types::{EthSpec, ExecutionPayloadHeader};
+
+pub fn run<T: EthSpec>(matches: &ArgMatches) -> Result<(), String> {
+    let eth1_block_hash = parse_required(matches, "execution-block-hash")?;
+    let genesis_time = parse_optional(matches, "genesis-time")?.unwrap_or(
+        SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .map_err(|e| format!("Unable to get time: {:?}", e))?
+            .as_secs(),
+    );
+    let base_fee_per_gas = Hash256::from_slice(&int_to_bytes32(parse_required(
+        matches,
+        "base-fee-per-gas",
+    )?));
+    let gas_limit = parse_required(matches, "gas-limit")?;
+    let file_name = matches.value_of("file").ok_or("No file supplied")?;
+
+    let execution_payload_header: ExecutionPayloadHeader<T> = ExecutionPayloadHeader {
+        gas_limit,
+        base_fee_per_gas,
+        timestamp: genesis_time,
+        block_hash: eth1_block_hash,
+        random: eth1_block_hash,
+        ..ExecutionPayloadHeader::default()
+    };
+    let mut file = File::create(file_name).map_err(|_| "Unable to create file".to_string())?;
+    let bytes = execution_payload_header.as_ssz_bytes();
+    file.write_all(bytes.as_slice())
+        .map_err(|_| "Unable to write to file".to_string())?;
+    Ok(())
+}