fix anaconda badge without hardcoded version (#2260)

Co-authored-by: Bouwe Andela <[email protected]>

README.md

@@ -7,7 +7,7 @@
 [![codecov](https://codecov.io/gh/ESMValGroup/ESMValCore/branch/main/graph/badge.svg?token=wQnDzguwq6)](https://codecov.io/gh/ESMValGroup/ESMValCore)
 [![Codacy Badge](https://app.codacy.com/project/badge/Grade/5d496dea9ef64ec68e448a6df5a65783)](https://www.codacy.com/gh/ESMValGroup/ESMValCore?utm_source=github.com&utm_medium=referral&utm_content=ESMValGroup/ESMValCore&utm_campaign=Badge_Grade)
 [![Docker Build Status](https://img.shields.io/docker/cloud/build/esmvalgroup/esmvalcore)](https://hub.docker.com/r/esmvalgroup/esmvalcore/)
-[![Anaconda-Server Badge](https://img.shields.io/badge/Anaconda.org-2.9.0-blue.svg)](https://anaconda.org/conda-forge/esmvalcore)
+[![Anaconda-Server Badge](https://img.shields.io/conda/vn/conda-forge/ESMValCore?color=blue&label=conda-forge&logo=conda-forge&logoColor=white)](https://anaconda.org/conda-forge/esmvalcore)
 [![Github Actions Test](https://github.com/ESMValGroup/ESMValCore/actions/workflows/run-tests.yml/badge.svg)](https://github.com/ESMValGroup/ESMValCore/actions/workflows/run-tests.yml)
 
 ![esmvaltoollogo](https://raw.githubusercontent.com/ESMValGroup/ESMValCore/main/doc/figures/ESMValTool-logo-2.png)