internal/containers/testdata: fix style issue in README

internal/containers/testdata/README.md

@@ -3,7 +3,7 @@
 The certificates in this directory has been generated with
 [generate_certs.bash].
 
-For more information, please see [Docker docs].
+For more information, see [Docker docs].
 
 [generate_certs.bash]: generate_certs.bash
 [Docker docs]: https://docs.docker.com/engine/security/protect-access/#use-tls-https-to-protect-the-docker-daemon-socket