fix: install faas-cli as a seperate CI step

[LucasRoesler]

Description

Run faas-cli install in it's own step to because this will install it into the users PATH for us and the setup/verify script will intelligently skip the faas-cli install step. This avoids a bug where the script assumes that the cli was installed into the tmp dir instead of the PATH.

Apparently, the runner now has enough permissions to do this, but it couldn't before.

Motivation and Context

• [ ] I have raised an issue to propose this change (required)

None, this was requested in Slack

Which issue(s) this PR fixes

NA

How Has This Been Tested?

The CI flow passed correctly in my fork.

Types of changes

• [x] 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)
• [ ] Version change (see: Impact to existing users)

Impact to existing users

None, this just fixes the CI process

Checklist:

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

[alexellis]

Thank you for the quick fix @LucasRoesler