use python 3.9 for lint, docs and deploy actions

3.7 is old and will soon be EOLed
this also fixes flake8 + importlib-metadata issues

.github/workflows/main.yml

@@ -86,7 +86,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v4
         with:
-          python-version: "3.7"
+          python-version: "3.9"
       - name: Set pip cache (Linux)
         uses: actions/cache@v3
         if: startsWith(runner.os, 'Linux')
@@ -110,7 +110,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v4
         with:
-          python-version: "3.7"
+          python-version: "3.9"
       - name: Set pip cache (Linux)
         uses: actions/cache@v3
         if: startsWith(runner.os, 'Linux')
@@ -136,7 +136,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v4
         with:
-          python-version: "3.7"
+          python-version: "3.9"
       - name: Check release
         id: check_release
         run: |

tox.ini

@@ -17,7 +17,7 @@ commands =
     pytest -s --cov=pelican pelican
 
 [testenv:docs]
-basepython = python3.7
+basepython = python3.9
 deps =
     -rrequirements/docs.pip
 changedir = docs
@@ -36,7 +36,7 @@ import-order-style = cryptography
 max-line-length = 88
 
 [testenv:flake8]
-basepython = python3.7
+basepython = python3.9
 deps =
     -rrequirements/style.pip
 commands =