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. The test introduced in d47fa16 is not enough, we need
to use a valid source URL.

tests/test_bom_create_releases.py

@@ -834,7 +834,7 @@ 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