test(bom createreleases): assure behaviour on diverging source URLs

In context of unconditional sourceUrl change introduced by commit
"feat: prevent uploading .git files", assure that existing, valid URLs
are not changed.

tests/test_bom_create_releases.py

@@ -779,10 +779,11 @@ def test_update_release_SourceUrl(self) -> None:
         item2 = Component(name="")
         CycloneDxSupport.update_or_set_ext_ref(
             item2, ExternalReferenceType.DISTRIBUTION,
-            CaPyCliBom.SOURCE_URL_COMMENT, "new_url")
+            CaPyCliBom.SOURCE_URL_COMMENT, "https://some.new/file.tar.gz")
         self.app.update_release(item2, release_data)
         captured = self.capsys.readouterr()  # type: ignore
         assert "differs from BOM URL" in captured.out
+        assert len(responses.calls) == 0  # assure data in SW360 is not changed
 
         # no existing URL, set new URL
         responses.add(