Bazel: prettify README.md.
Bazel: prettify README.md.

Change-Id: I98d12b94e4c657c8be886d2c97384f72b9d4db10
Signed-off-by: Piotr Sikora <ba6f3a1a6d7e1ecae91b31e93969cc392fbd0fdd@google.com>
Reviewed-on: https://nginx-review.googlesource.com/2641
Reviewed-by: Gurgen Hrachyan <50162806b3b8928bb34df830cfc0ce042562ff4e@google.com>

firebase/nginx,firebase/nginx,firebase/nginx,firebase/nginx