prepare for 21.10.0-RC1 (#2773)

Signed-off-by: garyschulte <garyschulte@gmail.com>

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## 21.10.0-RC1
+### Additions and Improvements
+
+### Bug Fixes
+
+### Early Access Features
+
+
 ## 21.7.4
 ### Additions and Improvements
 - Upgrade Gradle to 7.2, which supports building with Java 17 [#2761](https://github.com/hyperledger/besu/pull/2376) 
@@ -13,6 +21,10 @@
 - \[EXPERIMENTAL\] Added support for QBFT with PKI-backed Block Creation. [#2647](https://github.com/hyperledger/besu/issues/2647)
 - \[EXPERIMENTAL\] Added support for QBFT to use retrieve validators from a smart contract [#2574](https://github.com/hyperledger/besu/pull/2574)
 
+### Download Link
+https://hyperledger.jfrog.io/native/besu-binaries/besu/21.7.4/besu-21.7.4.zip \
+SHA256: 778d3c42851db11fec9171f77b22662f2baeb9b2ce913d7cfaaf1042ec19b7f9
+
 ## 21.7.3
 ### Additions and Improvements
 - Migration to Apache Tuweni 2.0 [\#2376](https://github.com/hyperledger/besu/pull/2376)

gradle.properties

@@ -1,4 +1,4 @@
-version=21.7.4
+version=21.10.0-RC1
 
 # Workaround for Java 16 and spotless bug 834 https://github.com/diffplug/spotless/issues/834
 org.gradle.jvmargs=--add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED \