Fix lint errors (#566)

Author: Gal Topper

Diff for: pkg/config/config.go

@@ -23,7 +23,6 @@ package config
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strings"
 	"sync"
@@ -354,7 +353,7 @@ func loadConfig(path string) (*V3ioConfig, error) {
 			return nil, errors.Wrap(err, "Failed to read the TSDB configuration.")
 		}
 	} else {
-		data, err = ioutil.ReadFile(resolvedPath)
+		data, err = os.ReadFile(resolvedPath)
 		if err != nil {
 			return nil, err
 		}

Diff for: test/benchmark/BenchmarkIngest_test.go

@@ -21,7 +21,7 @@ package benchmark
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"sync/atomic"
 	"testing"
@@ -55,7 +55,7 @@ func BenchmarkIngest(b *testing.B) {
 	defer metricReporter.Stop()
 
 	log.SetFlags(0)
-	log.SetOutput(ioutil.Discard)
+	log.SetOutput(io.Discard)
 	testStartTimeNano := time.Now().UnixNano()
 
 	var count = 0 // count real number of samples to compare with query result

Diff for: test/benchmark/common/config.go

@@ -21,7 +21,6 @@ package common
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -90,7 +89,7 @@ func loadBenchmarkIngestConfigFromFile(benchConfigFile string) (*BenchmarkIngest
 		benchConfigFile = filepath.Join(TsdbDefaultTestConfigPath, "tsdb-bench-test-config.yaml") // relative path
 	}
 
-	configData, err := ioutil.ReadFile(benchConfigFile)
+	configData, err := os.ReadFile(benchConfigFile)
 	if err != nil {
 		return nil, errors.Errorf("failed to load config from file %s", benchConfigFile)
 	}