Counteract CI bitrot

`pip install -U pip` was acting weird on Windows: use `python -m pip
install -U pip` instead.

Author: A5rocks

.github/workflows/ci.yml

@@ -13,9 +13,9 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Setup python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python }}
           cache: pip
@@ -43,9 +43,9 @@ jobs:
             extra_name: ', check formatting'
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Setup python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         if: "!endsWith(matrix.python, '-dev')"
         with:
           python-version: ${{ matrix.python }}
@@ -73,9 +73,9 @@ jobs:
         python: ['3.7', '3.8', '3.9', '3.10']
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Setup python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python }}
           cache: pip

ci.sh

@@ -4,7 +4,7 @@ set -ex
 
 YAPF_VERSION=0.20.1
 
-pip install -U pip setuptools wheel
+python -m pip install -U pip setuptools wheel
 
 python setup.py sdist --formats=zip
 pip install dist/*.zip