chore: remove refs to deprecated io/ioutil

pkg/systemlogmonitor/log_monitor.go

@@ -18,7 +18,7 @@ package systemlogmonitor
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"os"
 	"time"
 
 	"github.com/golang/glog"
@@ -62,7 +62,7 @@ func NewLogMonitorOrDie(configPath string) types.Monitor {
 		tomb:       tomb.NewTomb(),
 	}
 
-	f, err := ioutil.ReadFile(configPath)
+	f, err := os.ReadFile(configPath)
 	if err != nil {
 		glog.Fatalf("Failed to read configuration file %q: %v", configPath, err)
 	}

pkg/systemlogmonitor/logwatchers/filelog/log_watcher_test.go

@@ -17,7 +17,6 @@ limitations under the License.
 package filelog
 
 import (
-	"io/ioutil"
 	"os"
 	"testing"
 	"time"
@@ -139,7 +138,7 @@ Jan  2 03:04:05 kernel: [2.000000] 3
 	}
 	for c, test := range testCases {
 		t.Logf("TestCase #%d: %#v", c+1, test)
-		f, err := ioutil.TempFile("", "log_watcher_test")
+		f, err := os.CreateTemp("", "log_watcher_test")
 		assert.NoError(t, err)
 		defer func() {
 			f.Close()