set dependency check to only run occationally

.github/workflows/dependencies-check.yml

@@ -2,7 +2,7 @@ name: Dependencies Check
 
 on:
   schedule:
-  - cron: '30 19 * * *'
+  - cron: '43 3 * * 6,3'
   workflow_dispatch: {}
 
 jobs:
@@ -16,6 +16,8 @@ jobs:
     - uses: actions/checkout@v3
     - uses: samuelcolvin/list-python-dependencies@main
       id: list-python-dependencies
+      with:
+        mode: first-last
 
   test:
     name: test py${{ matrix.python-version }} on ${{ matrix.PYTHON_DEPENDENCY_CASE }}