fix: use virtual environment for CI actions

.github/workflows/ci.yaml

@@ -39,7 +39,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Install dependencies
-        run: python3 -m pip install tox
+        run: pipx install tox
       - name: Run linters
         run: tox run -e lint
 
@@ -50,7 +50,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Install dependencies
-        run: python3 -m pip install tox
+        run: pipx install tox
       - name: Run tests
         run: tox run -e unit
 
@@ -61,7 +61,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Install dependencies
-        run: python3 -m pip install tox
+        run: pipx install tox
       - name: Run tests
         run: tox run -e type
 

.github/workflows/nightly-TICS.yaml

@@ -15,10 +15,18 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Install dependencies
+      - name: Install requirements
         run: |
-          python3 -m pip install tox pylint flake8
-          python3 -m pip install --requirement test-requirements.txt
+          sudo apt update -y
+          sudo apt install python3-venv -y
+
+      - name: Create and activate virtual environment
+        run: |
+          python3 -m venv .venv
+          . .venv/bin/activate
+          pip install tox pylint flake8
+          pip install --requirement test-requirements.txt
+          echo PATH=$PATH >> $GITHUB_ENV
 
       - name: Run coverage tests
         run: |

.github/workflows/release.yaml

@@ -38,8 +38,8 @@ jobs:
       - name: Select charmhub channel
         uses: canonical/charming-actions/[email protected]
         id: channel
-      - name: Install dependencies
-        run: python3 -m pip install tox
+      - name: Install tox
+        run: pipx install tox
       - name: Stage charm
         run: tox run -e stage -- ${{ matrix.charm }} --clean
       - name: Upload charm to charmhub