ci: Remove tj-actions/changed-files github action since it's compromised (#241)

Author: hiagohubert

.github/workflows/build-test.yml

@@ -26,7 +26,7 @@ jobs:
 
       - name: Calculate file differences
         id: diff
-        uses: tj-actions/changed-files@v45
+        uses: step-security/changed-files@3dbe17c78367e7d60f00d78ae6781a35be47b4a1 # v45.0.1
         with:
           json: true
           escape_json: false