fix: datatype of targetAverageUtilization for Horizontal Pod Autoscaling

[Rishang]

For Horizontal Pod Autoscaling,

While using autoscaling based on targetAverageUtilization, in was facing this issue in DevSpace version : 6.0.1

Input:

  replicas: 1
  autoScaling:
    horizontal:  
      maxReplicas: 3
      averageRelativeMemory: 40

Error:

ValidationError(HorizontalPodAutoscaler.spec.metrics[0].resource.targetAverageUtilization): invalid type for io.k8s.api.autoscaling.v2beta1.ResourceMetricSource.targetAverageUtilization: got "string", expected "integer"

References:
https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale

targetAverageUtilization requires integer, but string was been given, so have prvided fixes for that.

[Rishang]

Fixes: for issue #81