* feat: Repository-wide RunnerDeployment Autoscaling
This adds `maxReplicas` and `minReplicas` to the RunnerDeploymentSpec. If and only if both fields are set, the controller computes and sets desired `replicas` automatically depending on the demand.
The number of demanded runner replicas is computed by `queued workflow runs + in_progress workflow runs` for the repository. The support for organizational runners is not included.
Ref https://github.com/summerwind/actions-runner-controller/issues/10
I had observed athe exact issue seen for the 4th option described in https://github.com/elastic/cloud-on-k8s/issues/1822, which resulted in actions-runner-controller is unable to create nor update runners. This fixes that.
I've also updated README to introduce RunnerDeployment and manually tested it to work after the fix.
---
`actions-runner-controller` has been failing while creating and updating runners:
```
2020-03-05T11:05:16.610+0900 ERROR controllers.Runner Failed to update runner {"runner": "default/example-runner", "error": "Runner.actions.summerwind.dev \"example-runner\" is invalid: []: Invalid value: map[string]interface {}{\"apiVersion\":\"actions.summerwind.dev/v1alpha1\", \"kind\":\"Runner\", \"metadata\":map[string]interface {}{\"creationTimestamp\":\"2020-03-05T02:05:16Z\", \"finalizers\":[]interface {}{\"runner.actions.summerwind.dev\"}, \"generation\":2, \"name\":\"example-runner\", \"namespace\":\"default\", \"resourceVersion\":\"911496\", \"selfLink\":\"/apis/actions.summerwind.dev/v1alpha1/namespaces/default/runners/example-runner\", \"uid\":\"48b62d07-ff2c-42d6-878c-d3f951202209\"}, \"spec\":map[string]interface {}{\"env\":interface {}(nil), \"image\":\"\", \"repository\":\"mumoshu/actions-runner-controller-ci\"}}: validation failure list:\nspec.env in body must be of type array: \"null\""}
github.com/go-logr/zapr.(*zapLogger).Error
/Users/c-ykuoka/go/pkg/mod/github.com/go-logr/zapr@v0.1.0/zapr.go:128
github.com/summerwind/actions-runner-controller/controllers.(*RunnerReconciler).Reconcile
/Users/c-ykuoka/p/actions-runner-controller/controllers/runner_controller.go:88
```
This seems like the exact issue seen in the 4th option in https://github.com/elastic/cloud-on-k8s/issues/1822
I also observed the same issue is failing while the runnerset controller is trying to create/update runners:
```
Also while creating runner in the runnerset controller:
2020-03-05T11:15:01.223+0900 ERROR controller-runtime.controller Reconciler error {"controller": "runnerset", "request": "default/example-runnerset", "error": "Runner.actions.summerwind.dev \"example-runnersetgp56m\" is invalid: []: Invalid value: map[string]interface {}{\"apiVersion\":\"actions.summerwind.dev/v1alpha1\", \"kind\":\"Runner\", \"metadata\":map[string]interface {}{\"creationTimestamp\":\"2020-03-05T02:15:01Z\", \"generateName\":\"example-runnerset\", \"generation\":1, \"name\":\"example-runnersetgp56m\", \"namespace\":\"default\", \"ownerReferences\":[]interface {}{map[string]interface {}{\"apiVersion\":\"actions.summerwind.dev/v1alpha1\", \"blockOwnerDeletion\":true, \"controller\":true, \"kind\":\"RunnerSet\", \"name\":\"example-runnerset\", \"uid\":\"e26f7d01-3168-496d-931b-8e6f97b776ea\"}}, \"uid\":\"4ee490f5-9a8c-4f30-86f9-61dea799b972\"}, \"spec\":map[string]interface {}{\"env\":interface {}(nil), \"image\":\"\", \"repository\":\"mumoshu/actions-runner-controller-ci\"}}: validation failure list:\nspec.env in body must be of type array: \"null\""}
github.com/go-logr/zapr.(*zapLogger).Error
```
and while the runnerdeployment controller is trying to create/update runners.
I've fixed it so that the new `RunnerDeployment` example added to README just works.