Upgrade prom and alert manager to 2.7.1 and 0.16.1

[LucasRoesler]

Description

• Removes the alert label in the scale-up alert
• Updates the annotaitons to use the function_name label instead of
  the instance label that was removed.
• Per why the alert always pending but not firing prometheus/prometheus#4836 and the related mailing list discussion
  https://groups.google.com/d/msg/prometheus-users/7Ul6ngc7Ogs/j_YDszV5BwAJ
  the alert value should not be included in the alert labels otherwise
  each calculation of the alert is treated like a new alert and then the
  use of for 5s will not behave as expected.
• Ports the resolution of Potential issues with AlertManager faas-netes#372

Motivation and Context

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

Resolves #1095

How Has This Been Tested?

Tested manually on my Mac

1. deploy via the script

./deploy_stack.sh

2. deploy the go-echo function https://github.com/alexellis/echo-fn
3. create constant load using hey

hey -c 2 -q 10 -n 100000 http://127.0.0.1:31112/function/go-echo

4. observe that the function scales in steps relatively quickly after the alert stops and that the function then scales quickly to 1 replica when the alert stops, this is shown in the below graphs

http://localhost:9090/graph?g0.range_input=15m&g0.expr=rate(gateway_function_invocation_total%5B10s%5D)&g0.tab=0&g1.range_input=15m&g1.expr=ALERTS%7Balertname%3D%22APIHighInvocationRate%22%7D&g1.tab=0&g2.range_input=15m&g2.expr=gateway_service_count&g2.tab=0

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.

[alexellis]

Thanks for putting this together. More unrelated changes than I expected around formatting and quotes, but if this still works as before I'll merge.

[alexellis]

Derek lock