[EIP-1559] Update hard block gas limit to 20M (#814)

Update hard block gas limit to 20M for EIP-1559 blocks.
Signed-off-by: Abdelhamid Bakhta <abdelhamid.bakhta@consensys.net>

* handmerge changelog

Signed-off-by: Abdelhamid Bakhta <abdelhamid.bakhta@consensys.net>

* Change block hard limit to 20M.

Signed-off-by: Abdelhamid Bakhta <abdelhamid.bakhta@consensys.net>

* Fixed unit test.

Signed-off-by: Abdelhamid Bakhta <abdelhamid.bakhta@consensys.net>

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/core/fees/FeeMarket.java

@@ -30,6 +30,6 @@ public interface FeeMarket {
   long getPerTxGaslimit();
 
   static FeeMarket eip1559() {
-    return new FeeMarketConfig(8L, 10000000L, 16000000L, 800000L, 10L, 1000000000L, 8000000L);
+    return new FeeMarketConfig(8L, 10000000L, 20000000L, 800000L, 10L, 1000000000L, 8000000L);
   }
 }

ethereum/core/src/test/java/org/hyperledger/besu/ethereum/core/fees/EIP1559BaseFeeTest.java

@@ -56,7 +56,7 @@ public class EIP1559BaseFeeTest {
           {MARKER_BASE_FEE, 5000, 918149673},
           {MARKER_BASE_FEE, 500000, 924641839},
           {MARKER_BASE_FEE, FEE_MARKET.getTargetGasUsed(), MARKER_BASE_FEE},
-          {MARKER_BASE_FEE, FEE_MARKET.getMaxGas(), 1127931889}
+          {MARKER_BASE_FEE, FEE_MARKET.getMaxGas(), 1180393837}
         });
   }