Improve generated integration tests

- Save logs from control(headscale) on every run to tmp
- Upgrade nix-actions
- Cancel builds if new commit is pushed
- Fix a sorting bug in user command test

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

integration/dockertestutil/logs.go

@@ -0,0 +1,68 @@
+package dockertestutil
+
+import (
+	"bytes"
+	"context"
+	"log"
+	"os"
+	"path"
+
+	"github.com/ory/dockertest/v3"
+	"github.com/ory/dockertest/v3/docker"
+)
+
+const filePerm = 0o644
+
+func SaveLog(
+	pool *dockertest.Pool,
+	resource *dockertest.Resource,
+	basePath string,
+) error {
+	err := os.MkdirAll(basePath, os.ModePerm)
+	if err != nil {
+		return err
+	}
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+
+	err = pool.Client.Logs(
+		docker.LogsOptions{
+			Context:      context.TODO(),
+			Container:    resource.Container.ID,
+			OutputStream: &stdout,
+			ErrorStream:  &stderr,
+			Tail:         "all",
+			RawTerminal:  false,
+			Stdout:       true,
+			Stderr:       true,
+			Follow:       false,
+			Timestamps:   false,
+		},
+	)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("Saving logs for %s to %s\n", resource.Container.Name, basePath)
+
+	err = os.WriteFile(
+		path.Join(basePath, resource.Container.Name+".stdout.log"),
+		stdout.Bytes(),
+		filePerm,
+	)
+	if err != nil {
+		return err
+	}
+
+	err = os.WriteFile(
+		path.Join(basePath, resource.Container.Name+".stderr.log"),
+		stderr.Bytes(),
+		filePerm,
+	)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}