Fix rtd and linkcheck/badge

.readthedocs.yml

@@ -1,6 +1,11 @@
 # Required
 version: 2
 
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "3.11"
+
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
   configuration: docs/conf.py
@@ -11,10 +16,7 @@ formats: []
 # Optionally set the version of Python and requirements required to build your
 # docs
 python:
-  version: 3.8
   install:
-    # Temporary workaround to have discretize wheels built.
-    - requirements: .rtd-requirements.txt
     - requirements: requirements-dev.txt
     - method: pip
       path: .

docs/dev/maintenance.rst

@@ -38,7 +38,7 @@ release.
      :target: https://coveralls.io/github/emsig/emg3d?branch=main
      :alt: Coveralls
   .. image:: https://app.codacy.com/project/badge/Grade/0412e617e8cd42fea05303fe490b09b5
-     :target: https://www.codacy.com/gh/emsig/emg3d/dashboard?utm_source=github.com&utm_medium=referral&utm_content=emsig/emg3d&utm_campaign=Badge_Grade
+     :target: https://app.codacy.com/gh/emsig/emg3d/dashboard?utm_source=github.com&utm_medium=referral&utm_content=emsig/emg3d&utm_campaign=Badge_Grade
      :alt: Codacy
 
   Check CI coverage and code quality is good.