Added eth_estimateGas fix and logs query known issue (#965)

Signed-off-by: Madeline <madeline.murray@consensys.net>

CHANGELOG.md

@@ -22,16 +22,11 @@ is owned by that user.
 
 The [1.5 release](docs/1_5_Upgrade.md) is scheduled for early July. 
 
-## 1.4.6
-
-### Additions and Improvements
-
-- Implemented WebSocket logs subscription for private contracts (`priv_subscribe`/`priv_unsubscribe`) [#762]
-
 ## 1.4.5
 
 ### Additions and Improvements
 
+- Implemented WebSocket logs subscription for private contracts (`priv_subscribe`/`priv_unsubscribe`) [#762]
 - Introduced SecurityModule plugin API. This allows use of a different security module as a plugin to 
   provide cryptographic function that can be used by NodeKey (such as sign, ECDHKeyAgreement etc.). KeyPairSecurityModule
   is registered and used by default. The CLI option `--security-module=<name> (defaults to localfile)` can be used 
@@ -43,6 +38,7 @@ The [1.5 release](docs/1_5_Upgrade.md) is scheduled for early July.
 
 ### Bug Fixes
 
+- Fixed `eth_estimateGas` JSON RPC so it no longer returns gas estimates that are too low. [\#842](https://github.com/hyperledger/besu/pull/842) 
 - Full help not displayed unless explicitly requested. [\#437](https://github.com/hyperledger/besu/pull/437)
 - Compatibility with undocumented Geth `eth_subscribe` fields. [\#654](https://github.com/hyperledger/besu/pull/654)
 - Current block number included as part of `eth_getWork` response. [\#849](https://github.com/hyperledger/besu/pull/849) 
@@ -51,6 +47,12 @@ The [1.5 release](docs/1_5_Upgrade.md) is scheduled for early July.
 
 Known issues are open issues categorized as [Very High or High impact](https://wiki.hyperledger.org/display/BESU/Defect+Prioritisation+Policy).
 
+#### New known issues 
+
+* Scope of logs query causing Besu to crash. [\#944](https://github.com/hyperledger/besu/pull/944) 
+
+Workaround - Limit the number of blocks queried by each `eth_getLogs` call. 
+
 #### Previously identified known issues
 
 - [`Intrinsic gas exceeds gas limit` returned when calling `delete mapping[addr]` or `mapping[addr] = 0`](KNOWN_ISSUES.md#intrinsic-gas-exceeds-gas-limit)