Actions: Use cache for pip

.github/workflows/test.yaml

@@ -46,9 +46,20 @@ jobs:
         uses: actions/setup-python@v2
         with:
           python-version: ${{ matrix.py }}
+
+      - uses: actions/cache@v2
+        with:
+          path: ~/.cache/pip
+          key: ${{ runner.os }}-pip-1
+          restore-keys: |
+            ${{ runner.os }}-pip-
+
+      - name: Install dependency
+        run: |
+          pip install -U cryptography PyNaCl pytest pytest-cov mock coveralls
+
       - name: Set up MySQL
         run: |
-          sleep 10
           mysql -h 127.0.0.1 -uroot -e "select version()"
           mysql -h 127.0.0.1 -uroot -e "SET GLOBAL local_infile=on"
           mysql -h 127.0.0.1 -uroot -e 'create database test1 DEFAULT CHARACTER SET utf8mb4'
@@ -59,7 +70,6 @@ jobs:
 
       - name: Run test
         run: |
-          pip install -U cryptography PyNaCl pytest pytest-cov mock coveralls
           pytest -v --cov --cov-config .coveragerc pymysql
 
       - name: Run MySQL8 auth test