Extend filter syntax with optional specification of file status: add, modified, deleted (#22)

* Add support for specification of change type (add,modified,delete)

* Use NULL as separator in git-diff command output

* Improve PR test workflow

* Fix the workflow file

.github/workflows/pull-request-verification.yml

@@ -70,3 +70,29 @@ jobs:
     - name: filter-test
       if: steps.filter.outputs.any != 'true' || steps.filter.outputs.error == 'true'
       run: exit 1
+
+  test-change-type:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - run: touch add.txt && rm README.md && echo "TEST" > LICENSE && git add -A
+    - uses: ./
+      id: filter
+      with:
+        token: ''
+        filters: |
+          add:
+            - added: "add.txt"
+          rm:
+            - deleted: "README.md"
+          modified:
+            - modified: "LICENSE"
+          any:
+            - added|deleted|modified: "*"
+    - name: filter-test
+      if: |
+        steps.filter.outputs.add != 'true'
+        || steps.filter.outputs.rm != 'true'
+        || steps.filter.outputs.modified != 'true'
+        || steps.filter.outputs.any != 'true'
+      run: exit 1