Document passing paths as CLI arguments in README

[TomasVotruba]

Adds 2 lines to the target-repository README explaining that paths can be passed directly as CLI arguments, before the --fix section.

Change

+Want to check specific paths instead of the configured ones? Pass them as arguments:
+
+```bash
+vendor/bin/ecs src tests
+```
+
 To actually **fix your code**, add `--fix`: