Add support for python 3.7 (#9)

* 使用setup-pdm准备环境，并增加python 3.7版本验证
* 部分包最新版本需要>=3.8，因此需要降低依赖版本
* 还是使用pdm来运行pytest
* fix pytest cov
* bump version

Support python 3.7

Author: asiazhang

.github/workflows/python-package.yml

@@ -15,19 +15,17 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [ "3.8", "3.9", "3.10", "3.11", "3.12" ]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12" ]
 
     steps:
       - uses: actions/checkout@v4
-      - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v4
+      - name: Set up PDM with python ${{ matrix.python-version }}
+        uses: pdm-project/setup-pdm@v4
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
         run: |
-          python -m pip install --upgrade pip
-          curl -sSL https://pdm-project.org/install-pdm.py | python3 -
-          pdm install -d
+          pdm sync -d -G dev
       - name: Lint with ruff
         run: |
           pdm run ruff check src
@@ -36,4 +34,4 @@ jobs:
           pdm run mypy src --strict
       - name: Test with pytest
         run: |
-          pdm run pytest --durations=5 --cov=. --cov-report term -vv
+          pdm run pytest --durations=5 --cov=. --cov-fail-under=90 --cov-report term -vv