Add explicit locking task

.github/workflows/pin_dependencies.yml

@@ -42,6 +42,10 @@ jobs:
       run: |
         pdm update np_workflows
         
+    - name: Add requirements.txt
+      run: | 
+        pdm lock --strategy inherit_metadata
+        
     - name: Add requirements.txt
       run: |
         pdm export --without-hashes -o requirements.txt