Fix SyntaxError introduced in a6451af

Author: adrien-berchet

src/tox_gh_actions/plugin.py

@@ -211,7 +211,7 @@ def is_log_grouping_enabled(options: Parsed) -> bool:
         elif isinstance(options.parallel, int) and options.parallel > 0:
             # Case for `tox p` or `tox -p <num>`
             return False
-        elif isinstance(options.parallel, int) and options.parallel = 0:
+        elif isinstance(options.parallel, int) and options.parallel == 0:
             # Case for `tox` or `tox -p 0`
             # tox will disable the parallel execution
             return True