fix workflow

Author: sth-v

.github/workflows/build-wheels.yml

@@ -18,7 +18,13 @@ jobs:
         python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
 
     steps:
-    - uses: actions/checkout@v4
+
+    - name: Check out repository
+      uses: actions/checkout@v4
+    - name: Extract branch name
+      shell: bash
+      run: echo "branch=${GITHUB_HEAD_REF:-${GITHUB_REF#refs/heads/}}" >> $GITHUB_OUTPUT
+      id: extract_branch
 
     # Ubuntu: Install CGAL and dependencies
     - name: Install CGAL on Ubuntu
@@ -70,8 +76,8 @@ jobs:
       id: cached-pip-wheels
       uses: actions/cache@v3
       with:
-        path: ~/.cache
-        key: venv-${{ runner.os }}-${{ steps.setup-python.outputs.python-version }}-${{ hashFiles('**/poetry.lock') }}
+          path: ~/.cache
+          key: venv-${{ runner.os }}-${{ steps.setup-python.outputs.python-version }}-${{ steps.extract_branch.outputs.branch }}
 
     - name: Install dependencies
       run: |
@@ -103,6 +109,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
+    - name: Extract branch name
+      shell: bash
+      run: echo "branch=${GITHUB_HEAD_REF:-${GITHUB_REF#refs/heads/}}" >> $GITHUB_OUTPUT
+      id: extract_branch
 
     - name: Set up Python
       id: setup-python
@@ -115,13 +125,12 @@ jobs:
       with:
         virtualenvs-create: true
         virtualenvs-in-project: true
-
     - name: Load cached venv
       id: cached-pip-wheels
       uses: actions/cache@v3
       with:
-        path: ~/.cache
-        key: venv-${{ runner.os }}-${{ steps.setup-python.outputs.python-version }}-${{ hashFiles('**/poetry.lock') }}
+          path: ~/.cache
+          key: venv-${{ runner.os }}-${{ steps.setup-python.outputs.python-version }}-${{ steps.extract_branch.outputs.branch }}
 
     - name: Install CGAL on Ubuntu
       run: |