Fix typo in openfaas_app example

[utsavanand2]

Signed-off-by: Utsav Anand utsavanand2@gmail.com

Description

Fixes a small typo in the openfaas_app example.
Changing the example from
arkade install openfaas --loadbalancer to
arkade install openfaas --load-balancer

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s
• I have added tests to cover my changes.
• All new and existing tests passed.

• I have tested this on arm, or have added code to prevent deployment

[alexellis]

LGTM