kill jobs if another push is made, also set the same shell for all steps

.github/workflows/CI.yaml

@@ -15,6 +15,14 @@ on:
     #   (from https://help.github.com/en/actions/reference/events-that-trigger-workflows#scheduled-events-schedule)
     - cron: "0 0 * * 0"
 
+concurrency:
+  group: "${{ github.workflow }}-${{ github.ref }}"
+  cancel-in-progress: true
+
+defaults:
+  run:
+    shell: bash -l {0}
+
 jobs:
   test:
     name: Test on ${{ matrix.os }}, Python ${{ matrix.python-version }}
@@ -64,7 +72,6 @@ jobs:
       - uses: actions/checkout@v3
 
       - name: Additional info about the build
-        shell: bash
         run: |
           uname -a
           df -h
@@ -81,14 +88,12 @@ jobs:
 
       - name: Install package
         # conda setup requires this special shell
-        shell: bash -l {0}
         run: |
           python -m pip install . --no-deps
           micromamba list
 
       - name: Run tests
         # conda setup requires this special shell
-        shell: bash -l {0}
         run: |
           pytest -v --cov=modelforge --cov-report=xml --color=yes modelforge/tests/