Link release badge to documentation (#2089)

* Link release badge to documentation

I already caught myself several times clicking the release badge and expecting to get to the docs of that version. Now it should work

* Link to stable instead of specific relewase

* update release badge link; move docs badge

Author: lindnemi

README.md

@@ -3,9 +3,9 @@ SPDX-FileCopyrightText: Contributors to PyPSA-Eur <https://github.com/pypsa/pyps
 SPDX-License-Identifier: CC-BY-4.0
 -->
 
-![GitHub release (latest by date including pre-releases)](https://img.shields.io/github/v/release/pypsa/pypsa-eur?include_prereleases)
-[![Test workflows](https://github.com/pypsa/pypsa-eur/actions/workflows/test.yaml/badge.svg)](https://github.com/pypsa/pypsa-eur/actions/workflows/test.yaml)
+[![GitHub release (latest by date including pre-releases)](https://img.shields.io/github/v/release/pypsa/pypsa-eur?include_prereleases)](https://github.com/PyPSA/pypsa-eur/releases)
 [![Documentation](https://readthedocs.org/projects/pypsa-eur/badge/?version=latest)](https://pypsa-eur.readthedocs.io/en/latest/?badge=latest)
+[![Test workflows](https://github.com/pypsa/pypsa-eur/actions/workflows/test.yaml/badge.svg)](https://github.com/pypsa/pypsa-eur/actions/workflows/test.yaml)
 ![Size](https://img.shields.io/github/repo-size/pypsa/pypsa-eur)
 [![Zenodo PyPSA-Eur](https://zenodo.org/badge/DOI/10.5281/zenodo.3520874.svg)](https://doi.org/10.5281/zenodo.3520874)
 [![Zenodo PyPSA-Eur-Sec](https://zenodo.org/badge/DOI/10.5281/zenodo.3938042.svg)](https://doi.org/10.5281/zenodo.3938042)