updated changelog for 1.0.3

CHANGELOG.md

@@ -1,6 +1,16 @@
 # System Test Releases
 
 
+#### 1.0.3
+
+* Modified test framework, [system-test, #21](https://github.com/stellar/system-test/pull/21), to build [Stellar Quickstart](https://github.com/stellar/quickstart) as the base image.  
+Refer to [README.md](https://github.com/stellar/system-test#readme) for new two step process of running tests:  
+(1) run make with server versions, creates docker image  
+(2) run the docker image to run tests.  
+
+
+This version of tests is based on [Soroban Preview 7](https://soroban.stellar.org/docs/releases) system interfaces. 
+
 
 #### 1.0.2