chore: updates the license badge (#6058)

substrate/README.md

-# Substrate · [![GitHub license](https://img.shields.io/github/license/paritytech/substrate)](LICENSE) [![GitLab Status](https://gitlab.parity.io/parity/substrate/badges/master/pipeline.svg)](https://gitlab.parity.io/parity/substrate/pipelines) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](docs/CONTRIBUTING.adoc)
+# Substrate · [![GitHub license](https://img.shields.io/badge/license-GPL3%2FApache2-blue)](LICENSE) [![GitLab Status](https://gitlab.parity.io/parity/substrate/badges/master/pipeline.svg)](https://gitlab.parity.io/parity/substrate/pipelines) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](docs/CONTRIBUTING.adoc)
 
 <p align="center">
   <img src="/docs/media/sub.gif">
@@ -21,4 +21,4 @@ The security policy and procedures can be found in [`docs/SECURITY.md`](docs/SEC
 
 ## License
 
-Substrate Client (`/client/*` / `sc-*`) is licensed under [GPL v3.0 with a classpath linking exception](LICENSE-GPL3), primitives (`sp-*`), FRAME (`frame-*`) and pallets (`pallets-*`), binaries (`/bin`) and all other utilities are licensed under [Apache 2.0](LICENSE-APACHE2).
\ No newline at end of file
+Substrate Client (`/client/*` / `sc-*`) is licensed under [GPL v3.0 with a classpath linking exception](LICENSE-GPL3), primitives (`sp-*`), FRAME (`frame-*`) and pallets (`pallets-*`), binaries (`/bin`) and all other utilities are licensed under [Apache 2.0](LICENSE-APACHE2).