Add temporary workaround for coveralls

.cirrus.yml

@@ -52,7 +52,8 @@ env:
     -n 5 --randomly-seed=42 -rfEx --durations 10 --color yes
   submit_coverage_script:
     - pipx run coverage xml -o coverage.xml
-    - pipx run coveralls --submit coverage.xml
+    - pipx run 'coveralls<4' --submit coverage.xml
+      # ^-- https://github.com/TheKevJames/coveralls-python/issues/434
 
 # Deep clone script for POSIX environments (required for setuptools-scm)
 .clone_script: &clone |
@@ -159,7 +160,8 @@ finalize_task:
   container: {image: "python:3.10-bullseye"}
   depends_on: [test]
   <<: *task-template
-  install_script: pip install coveralls
+  install_script: pip install 'coveralls<4'
+    # ^-- https://github.com/TheKevJames/coveralls-python/issues/434
   finalize_coverage_script: coveralls --finish
 
 linkcheck_task: