Change health checks to healthchecks in watchdog README

Signed-off-by: Jonatas Baldin <jonatas.baldin@gmail.com>

watchdog/README.md

@@ -199,7 +199,7 @@ To override the Content-Type of all your responses set the `content_type` enviro
 
 This is an unsupported use-case for the OpenFaaS project however if your container conforms to the requirements below then the OpenFaaS API gateway and other tooling will manage and scale your service.
 
-You will need to provide a lock-file at `/tmp/.lock` so that the orchestration system can run health checks on your container. If you are using Docker Swarm make sure you provide a `HEALTHCHECK` instruction in your Dockerfile - samples are given in the `faas` repository.
+You will need to provide a lock-file at `/tmp/.lock` so that the orchestration system can run healthchecks on your container. If you are using Docker Swarm make sure you provide a `HEALTHCHECK` instruction in your Dockerfile - samples are given in the `faas` repository.
 
 * Expose TCP port 8080 over HTTP
 * Create `/tmp/.lock` or in whatever location responds to the OS tempdir syscall