CI: fix CI badges in README

Author: mloubout

README.md

@@ -1,8 +1,8 @@
 # Devito: Fast Stencil Computation from Symbolic Specification
 
-[![Build Status for the Core backend](https://github.com/devitocodes/devito/workflows/CI-core/badge.svg)](https://github.com/devitocodes/devito/actions?query=workflow%3ACI-core)
-[![Build Status with MPI](https://github.com/devitocodes/devito/workflows/CI-mpi/badge.svg)](https://github.com/devitocodes/devito/actions?query=workflow%3ACI-mpi)
-[![Build Status on GPU](https://github.com/devitocodes/devito/workflows/CI-gpu/badge.svg)](https://github.com/devitocodes/devito/actions?query=workflow%3ACI-gpu)
+[![Build Status for the Core backend](https://github.com/devitocodes/devito/actions/workflows/pytest-core-nompi.yml/badge.svg?branch=main)](https://github.com/devitocodes/devito/actions/workflows/pytest-core-nompi.yml)
+[![Build Status with MPI](https://github.com/devitocodes/devito/actions/workflows/pytest-core-mpi.yml/badge.svg?branch=main)](https://github.com/devitocodes/devito/actions/workflows/pytest-core-mpi.yml)
+[![Build Status on GPU](https://github.com/devitocodes/devito/actions/workflows/pytest-gpu.yml/badge.svg?branch=main)](https://github.com/devitocodes/devito/actions/workflows/pytest-gpu.yml)
 [![Code Coverage](https://codecov.io/gh/devitocodes/devito/branch/main/graph/badge.svg)](https://codecov.io/gh/devitocodes/devito)
 [![Slack Status](https://img.shields.io/badge/chat-on%20slack-%2336C5F0)](https://join.slack.com/t/devitocodes/shared_invite/zt-2hgp6891e-jQDcepOWPQwxL5JJegYKSA)
 [![asv](http://img.shields.io/badge/benchmarked%20by-asv-blue.svg?style=flat)](https://devitocodes.github.io/devito-performance)