ci: Silence unnecessary warning

actions/setup-python#809

Author: Synss

.github/workflows/main.yml

@@ -14,6 +14,8 @@ jobs:
         os: [ubuntu-latest, macos-latest, windows-latest]
         pyver: [cp38, cp39, cp310, cp311, cp312]
         version: [2.28.8]
+    env:
+      PIP_DISABLE_PIP_VERSION_CHECK: 1
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5