Upgrade pyright (#8110)

Author: AlexWaygood

.github/workflows/tests.yml

@@ -77,7 +77,7 @@ jobs:
         python-version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11"]
       fail-fast: false
     env:
-      PYRIGHT_VERSION: 1.1.254 # Must match pyright_test.py.
+      PYRIGHT_VERSION: 1.1.255 # Must match pyright_test.py.
     steps:
       - uses: actions/checkout@v2
       - uses: jakebailey/pyright-action@v1

tests/pyright_test.py

@@ -5,7 +5,7 @@
 import sys
 from pathlib import Path
 
-_PYRIGHT_VERSION = "1.1.254"  # Must match .github/workflows/tests.yml.
+_PYRIGHT_VERSION = "1.1.255"  # Must match .github/workflows/tests.yml.
 _WELL_KNOWN_FILE = Path("tests", "pyright_test.py")