Merge pull request #212623 from ckiee/step-ca-0-23-1-test-no-parallel

step-ca: fix flaky test parallelism

pkgs/tools/security/step-ca/default.nix

···
   # Tests start http servers which need to bind to local addresses:
   # panic: httptest: failed to listen on a port: listen tcp6 [::1]:0: bind: operation not permitted
   __darwinAllowLocalNetworking = true;
+  # Tests need to run in a reproducible order, otherwise they run unreliably on
+  # (at least) x86_64-linux.
+  checkFlags = [ "-p 1" ];
 
   passthru.tests.step-ca = nixosTests.step-ca;