Faas-cli binary template for linux amd64

[Waterdrips]

Description

faas-cli binary template did not have a amd64 linux branch in the
template.
This was reported under #173

Tested on linux amd64

Signed-off-by: Alistair Hey alistair@heyal.co.uk

Motivation and Context

• I have raised an issue to propose this change (required)
  ark get faas-cli yields 404 #173

How Has This Been Tested?

go build
./arkade get faas-cli

Downloading faas-cli
https://github.com/openfaas/faas-cli/releases/download/0.12.8/faas-cli
Tool written to: /tmp/faas-cli

Run the following to copy to install the tool:

chmod +x /tmp/faas-cli
sudo install -m 755 /tmp/faas-cli /usr/local/bin/faas-cli

On amd64 linux

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

[alexellis]

Is there a unit test that could be added for regression testing? Did I miss this scenario in the tests?

[alexellis]

I can do the test..