Stop using ioutil package

Makefile

@@ -8,7 +8,7 @@ endif
 
 .PHONY: lint
 lint:
-	docker run --rm -v $(shell pwd):/app -w /app golangci/golangci-lint:v1.43.0 golangci-lint run -c .golangci.yaml
+	docker run --rm -v $(shell pwd):/app -w /app golangci/golangci-lint:v1.51.1 golangci-lint run -c .golangci.yaml
 
 .PHONY: tests
 tests:

README.md

@@ -98,7 +98,7 @@ rows:
 Dashboard creation (or [automatically as a Kubernetes Resource, using DARK](https://github.com/K-Phoen/dark)):
 
 ```go
-content, err := ioutil.ReadFile("dashboard.yaml")
+content, err := os.ReadFile("dashboard.yaml")
 if err != nil {
     fmt.Fprintf(os.Stderr, "Could not read file: %s\n", err)
     os.Exit(1)

client.go

@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 )
 
@@ -61,7 +60,7 @@ func (client *Client) modifyRequest(request *http.Request) {
 }
 
 func (client Client) httpError(resp *http.Response) error {
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return err
 	}

dashboards_test.go

@@ -3,21 +3,20 @@ package grabana
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
 
 	"github.com/K-Phoen/sdk"
+	"github.com/stretchr/testify/require"
 
 	"github.com/K-Phoen/grabana/alert"
-
 	"github.com/K-Phoen/grabana/dashboard"
 	"github.com/K-Phoen/grabana/row"
 	"github.com/K-Phoen/grabana/text"
 	"github.com/K-Phoen/grabana/timeseries"
-	"github.com/stretchr/testify/require"
 )
 
 func TestADashboardCanBeFoundByTitle(t *testing.T) {
@@ -842,7 +841,7 @@ func TestDashboardsCanBeCreatedWithNewAlertsAndDeletesPreviousAlerts(t *testing.
 		// new alert creation
 		if r.Method == http.MethodPost && r.URL.String() == "/api/ruler/grafana/api/v1/rules/Folder%20name" {
 			newAlertCreated = true
-			body, err := ioutil.ReadAll(r.Body)
+			body, err := io.ReadAll(r.Body)
 			req.NoError(err)
 
 			req.JSONEq(`{

doc/unmarshalling_yaml.md

@@ -11,7 +11,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 
 	"github.com/K-Phoen/grabana/decoder"
@@ -20,7 +19,7 @@ import (
 func main() {
 	filePath := "some/awesome/dashboard.yaml"
 
-	content, err := ioutil.ReadFile(filePath)
+	content, err := os.ReadFile(filePath)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Could not read file: %s\n", err)
 		os.Exit(1)