Fix typo in secrets example

[john-g-g]

The secrets example proposes a test1234 as the value of api-key but in the example is uses 1234 as the value.

Proposed change

Change the value in the example to test1234

Context

Briefly confusion before concluding it was a typo

Your Environment

• FaaS-CLI version ( Full output from: faas-cli version ):

• Docker version docker version (e.g. Docker 17.0.05 ):

• Are you using Docker Swarm or Kubernetes (FaaS-netes)?

• Operating System and version (e.g. Linux, Windows, MacOS):

• Link to your project or a code example to reproduce issue:

• Please also follow the troubleshooting guide and paste in any other diagnostic information you have: