feat: Organizational RunnerDeployment Autoscaling

Enhances #57 to add support for organizational runners.

As GitHub Actions does not have an appropriate API for this, this is the spec you need:

```
apiVersion: actions.summerwind.dev/v1alpha1
kind: RunnerDeployment
metadata:
  name: myrunners
spec:
  minReplicas: 1
  maxReplicas: 3
  autoscaling:
    metrics:
    - type: TotalNumberOfQueuedAndProgressingWorkflowRuns
      repositories:
      # Assumes that you have `github.com/myorg/myrepo1` repo
      - myrepo1
      - myrepo2
  template:
    spec:
      organization: myorg
```

It works by collecting "in_progress" and "queued" workflow runs for the repositories `myrepo1` and `myrepo2` to autoscale the number of replicas, assuming you have this organizational runner deployment only for those two repositories.

For example, if `myrepo1` had 1 `in_progress` and 2 `queued` workflow runs, and `myrepo2` had 4 `in_progress` and 8 `queued` workflow runs at the time of running the reconcilation loop on the runner deployment, it will scale replicas to 1 + 2 + 4 + 8 = 15.

Perhaps we might be better add a kind of "ratio" setting so that you can configure the controller to create e.g. 2x runners than demanded. But that's another story.

Ref #10

api/v1alpha1/runnerdeployment_types.go

@@ -20,6 +20,10 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
+const (
+	AutoscalingMetricTypeTotalNumberOfQueuedAndProgressingWorkflowRuns = "TotalNumberOfQueuedAndProgressingWorkflowRuns"
+)
+
 // RunnerReplicaSetSpec defines the desired state of RunnerDeployment
 type RunnerDeploymentSpec struct {
 	// +optional
@@ -38,9 +42,28 @@ type RunnerDeploymentSpec struct {
 	// +optional
 	ScaleDownDelaySecondsAfterScaleUp *int `json:"scaleDownDelaySecondsAfterScaleOut,omitempty"`
 
+	// Autoscaling is set various configuration options for autoscaling this runner deployment.
+	// +optional
+	Autoscaling AutoscalingSpec `json:"autoscaling,omitempty"`
+
 	Template RunnerTemplate `json:"template"`
 }
 
+type AutoscalingSpec struct {
+	Metrics []MetricSpec `json:"metrics,omitempty"`
+}
+
+type MetricSpec struct {
+	// Type is the type of metric to be used for autoscaling.
+	// The only supported Type is TotalNumberOfQueuedAndProgressingWorkflowRuns
+	Type string `json:"type,omitempty"`
+
+	// RepositoryNames is the list of repository names to be used for calculating the metric.
+	// For example, a repository name is the REPO part of `github.com/USER/REPO`.
+	// +optional
+	RepositoryNames []string `json:"repositoryNames,omitempty"`
+}
+
 type RunnerDeploymentStatus struct {
 	AvailableReplicas int `json:"availableReplicas"`
 	ReadyReplicas     int `json:"readyReplicas"`

api/v1alpha1/zz_generated.deepcopy.go

@@ -25,6 +25,48 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 )
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *AutoscalingSpec) DeepCopyInto(out *AutoscalingSpec) {
+	*out = *in
+	if in.Metrics != nil {
+		in, out := &in.Metrics, &out.Metrics
+		*out = make([]MetricSpec, len(*in))
+		for i := range *in {
+			(*in)[i].DeepCopyInto(&(*out)[i])
+		}
+	}
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new AutoscalingSpec.
+func (in *AutoscalingSpec) DeepCopy() *AutoscalingSpec {
+	if in == nil {
+		return nil
+	}
+	out := new(AutoscalingSpec)
+	in.DeepCopyInto(out)
+	return out
+}
+
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *MetricSpec) DeepCopyInto(out *MetricSpec) {
+	*out = *in
+	if in.RepositoryNames != nil {
+		in, out := &in.RepositoryNames, &out.RepositoryNames
+		*out = make([]string, len(*in))
+		copy(*out, *in)
+	}
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new MetricSpec.
+func (in *MetricSpec) DeepCopy() *MetricSpec {
+	if in == nil {
+		return nil
+	}
+	out := new(MetricSpec)
+	in.DeepCopyInto(out)
+	return out
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *Runner) DeepCopyInto(out *Runner) {
 	*out = *in
@@ -134,6 +176,7 @@ func (in *RunnerDeploymentSpec) DeepCopyInto(out *RunnerDeploymentSpec) {
 		*out = new(int)
 		**out = **in
 	}
+	in.Autoscaling.DeepCopyInto(&out.Autoscaling)
 	in.Template.DeepCopyInto(&out.Template)
 }