GitHub Actions: Pin ruff to the same version as pre-commit

Similar to #395
but centralizing it in requirements.txt

.github/workflows/python-app.yml

@@ -21,8 +21,7 @@ jobs:
                     # Run as a non-root user to avoid cheribuild errors
                     adduser --disabled-password --gecos "Not Root" notroot
                     su -c "python -m pip install --user --upgrade pip" notroot
-                    su -c " pip install --user --upgrade flake8 pytest" notroot
-                    su -c "if [ -f requirements.txt ]; then pip install --user -r requirements.txt; fi" notroot
+                    su -c "pip install --user -r requirements.txt" notroot
             -   name: Lint with flake8
                 run: |
                     # stop the build if there are any flake8 warnings
@@ -38,8 +37,8 @@ jobs:
                     # Use the system-provided python3 instead of actions/setup-python@v4
                     python3 --version
                     python3 -m pip install --upgrade pip
-                    python3 -m pip install --upgrade flake8 pytest ruff pre-commit
-                    if [ -f requirements.txt ]; then python3 -m pip install -r requirements.txt; fi
+                    python3 -m pip install --upgrade pre-commit
+                    python3 -m pip install -r requirements.txt
             -   name: Lint with flake8
                 run: flake8
             -   name: Lint with ruff
@@ -60,7 +59,7 @@ jobs:
             -   name: Install dependencies
                 run: |
                     python -m pip install --upgrade pip
-                    pip install --upgrade flake8 ruff pre-commit
+                    pip install --upgrade pre-commit
                     if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
             -   name: Lint with flake8
                 run: flake8

tests/requirements.txt

@@ -5,3 +5,4 @@ argcomplete>=2.0.0
 # Only needed for RISC-V FPGA boot -> not bundled
 pyserial>=3.5
 flake8
+ruff==0.3.4