Update CHANGELOG.md

Author: jbern0rd

CHANGELOG.md

@@ -14,6 +14,7 @@ All notable changes to this project will be documented in this file.
 - Upgrade to `eclipse-temurin` 11.0.20. (#95)
 - Upgrade to Spring Boot 2.7.14. (#96)
 - Upgrade to Spring Dependency Management Plugin 1.1.3. (#96)
+- Upgrade to `jenkins-library` 2.7.3. (#100)
 
 ## [[8.1.1]](https://github.com/iExecBlockchainComputing/iexec-result-proxy/releases/tag/v8.1.1) 2023-06-23