Allow setting deployment replicas

What does this MR do?

Allows setting the number of runner pods to greater than 1

Why was this MR needed?

Need to scale to multiple replicas in Orka

What's the best way to test this MR?

Add to your values.yaml

replicas: 10

helm template test . should show the config map being added

# Source: gitlab-runner/templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: test-gitlab-runner
  labels:
    app: test-gitlab-runner
    chart: gitlab-runner-0.27.0-beta
    release: "test"
    heritage: "Helm"
spec:
  replicas: 10
  
  ...

What are the relevant issue numbers?

gitlab-org/ci-cd/custom-executor-drivers/autoscaler#65 (closed)