avoid broken pyright version

Author: maxbachmann

.github/workflows/branchbuild.yml

@@ -158,7 +158,7 @@ jobs:
       - name: Install testing dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install pytest hypothesis pandas mypy pyright pyinstaller[hook_testing]
+          pip install pytest hypothesis pandas mypy pyright==1.1.400 pyinstaller[hook_testing]
 
       - name: Test type stubs
         run: |