check-manifest is not needed to run tests.

--- pytest_run_parallel-0.8.2/pyproject.toml.orig
+++ pytest_run_parallel-0.8.2/pyproject.toml
@@ -58,7 +58,6 @@
     "pytest-order",
     "pytest-xdist",
     "hypothesis>=6.135.33",
-    "check-manifest",
 ]
 dev = [
     { include-group = "test" },