Update badge link: stages → maturity in README.md (#868)

Signed-off-by: Juan Estrella <juan.estrella@finos.org>

Author: TheJuanAndOnly99

README.md

@@ -1,5 +1,5 @@
 [![Build](https://github.com/finos/symphony-bdk-java/actions/workflows/build.yml/badge.svg)](https://github.com/finos/symphony-bdk-java/actions/workflows/build.yml)
-[![FINOS - Active](https://cdn.jsdelivr.net/gh/finos/contrib-toolbox@master/images/badge-active.svg)](https://community.finos.org/docs/governance/Software-Projects/stages/active)
+[![FINOS - Graduated](https://cdn.jsdelivr.net/gh/finos/contrib-toolbox@master/images/badge-graduated.svg)](https://community.finos.org/docs/governance/lifecycle-stages/graduated)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![Maven Central](https://maven-badges.herokuapp.com/maven-central/org.finos.symphony.bdk/symphony-bdk-bom/badge.svg)](https://maven-badges.herokuapp.com/maven-central/org.finos.symphony.bdk/symphony-bdk-bom)
 [![javadoc](https://javadoc.io/badge2/org.finos.symphony.bdk/symphony-bdk-core/javadoc.svg)](https://javadoc.io/doc/org.finos.symphony.bdk/symphony-bdk-core)
@@ -92,4 +92,4 @@ Copyright 2021 Symphony LLC
 
 Distributed under the [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0).
 
-SPDX-License-Identifier: [Apache-2.0](https://spdx.org/licenses/Apache-2.0)
+SPDX-License-Identifier: [Apache-2.0](https://spdx.org/licenses/Apache-2.0)