.github/workflows: adjust flake8 lint action

It is picking up the virtual environment in .venv and failing on a
bunch of code unrelated to ours.

Author: alanorth

.github/workflows/python-app.yml

@@ -36,9 +36,9 @@ jobs:
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names
-        uv run flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+        uv run flake8 src --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-        uv run flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+        uv run flake8 src --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
     - name: Set up PostgreSQL
       run: |
         pg_isready -U postgres -d dspacestatistics