update min py ver to 3.9

.github/workflows/build.yml

@@ -26,16 +26,10 @@ jobs:
         - name: Install dependencies
           run: |
             python -m pip install --upgrade pip
-            pip install configobj==5.0.6
-            pip install numpy==1.20.3
-            pip install pandas==1.2.4
-            pip install scipy==1.6.3
-            pip install requests==2.25.1
-            pip install xarray==0.20.2 
-            pip install git+https://github.com/JGCRI/gcamreader.git
+            python -m pip install .
 
         - name: Test and generate coverage report
           run: |
-            pip install pytest
-            pip install pytest-cov
+            python -m pip install pytest
+            python -m pip install pytest-cov
             pytest --cov=./ --cov-report=xml

setup.py

@@ -16,7 +16,7 @@ def readme():
 setup(
     name='demeter',
     version=version,
-    python_requires=">=3.7.1",
+    python_requires=">=3.9",
     packages=find_packages(),
     url='https://github.com/JGCRI/demeter',
     license='BSD 2-Clause',
@@ -32,8 +32,8 @@ def readme():
         'scipy>=1.6.3',
         'requests>=2.20.0',
         'gcamreader>=1.2.5',
-        'xarray>= 0.20.2',
-        'netcdf4>= 1.6.4',
+        'xarray>=0.20.2',
+        'netcdf4>=1.6.4',
         'matplotlib>=3.4.2',
     ],
     include_package_data=True