Fix broken k3s preset (permission denied error)

Github issues for context:
actions/runner-images#3673
#208

FAQ entry on k3s.io:
https://k3d.io/faq/faq/#solved-nodes-fail-to-start-or-get-stuck-in-notready-state-with-log-nf_conntrack_max-permission-denied

README.md

@@ -128,7 +128,7 @@ MongoDB | [Go package](https://github.com/orlangure/gnomock/tree/master/preset/m
 RabbitMQ | [Go package](https://github.com/orlangure/gnomock/tree/master/preset/rabbitmq) | [Docs](https://app.swaggerhub.com/apis/orlangure/gnomock/1.5.0#/presets/startRabbitMq) | [Reference](https://pkg.go.dev/github.com/orlangure/gnomock/preset/rabbitmq?tab=doc) | `3.8.9-alpine`, `3.8.9-management-alpine`
 Kafka | [Go package](https://github.com/orlangure/gnomock/tree/master/preset/kafka) | [Docs](https://app.swaggerhub.com/apis/orlangure/gnomock/1.5.0#/presets/startKafka) | [Reference](https://pkg.go.dev/github.com/orlangure/gnomock/preset/kafka?tab=doc) | `2.5.1-L0`
 Elasticsearch | [Go package](https://github.com/orlangure/gnomock/tree/master/preset/elastic) | [Docs](https://app.swaggerhub.com/apis/orlangure/gnomock/1.5.0#/presets/startElastic) | [Reference](https://pkg.go.dev/github.com/orlangure/gnomock/preset/elastic?tab=doc) | `5.6`, `6.8.13`, `7.9.3`
-Kubernetes | [Go package](https://github.com/orlangure/gnomock/tree/master/preset/k3s) | [Docs](https://app.swaggerhub.com/apis/orlangure/gnomock/1.5.0#/presets/startKubernetes) | [Reference](https://pkg.go.dev/github.com/orlangure/gnomock/preset/k3s?tab=doc) | `v1.19.3`
+Kubernetes | [Go package](https://github.com/orlangure/gnomock/tree/master/preset/k3s) | [Docs](https://app.swaggerhub.com/apis/orlangure/gnomock/1.5.0#/presets/startKubernetes) | [Reference](https://pkg.go.dev/github.com/orlangure/gnomock/preset/k3s?tab=doc) | `v1.19.12`
 CockroachDB | [Go package](https://github.com/orlangure/gnomock/tree/master/preset/cockroachdb) | [Docs](https://app.swaggerhub.com/apis/orlangure/gnomock/1.5.0#/presets/startCockroachDB) | [Reference](https://pkg.go.dev/github.com/orlangure/gnomock/preset/cockroachdb?tab=doc) | `v19.2.11`, `v20.1.10`
 InfluxDB | [Go package](https://github.com/orlangure/gnomock/tree/master/preset/influxdb) | [Docs](https://app.swaggerhub.com/apis/orlangure/gnomock/1.5.0#/presets/startInfluxDB) | [Reference](https://pkg.go.dev/github.com/orlangure/gnomock/preset/influxdb?tab=doc) | `2.0.4-alpine`
 <!-- new presets go here -->

preset/k3s/preset.go

@@ -9,9 +9,16 @@
 // https://github.com/orlangure/k3s-dind.
 //
 // Please make sure to pick a version here:
-// https://hub.docker.com/repository/docker/orlangure/k3s. At some point k3s
-// version tags should start to appear. If only `latest` tag is available, it
-// comes with k3s v1.18.4.
+// https://hub.docker.com/repository/docker/orlangure/k3s.
+//
+// The following versions include important fixes that prevent this preset from
+// working on recent Linux Kernel versions, please make sure to avoid using
+// older versions for each API level:
+//
+// 	v1.18.19
+// 	v1.19.11
+// 	v1.20.7
+// 	v1.21.1
 //
 // Keep in mind that k3s runs in a single docker container, meaning it might be
 // limited in memory, CPU and storage. Also remember that this cluster always

preset/k3s/preset_test.go

@@ -17,7 +17,7 @@ func TestPreset(t *testing.T) {
 
 	p := k3s.Preset(
 		k3s.WithPort(48448),
-		k3s.WithVersion("v1.19.3"),
+		k3s.WithVersion("v1.19.12"),
 	)
 	c, err := gnomock.Start(
 		p,