Replace deprecated ioutil pkg with os & io

As of Go 1.16, the same functionality is now provided by package io or
package os, and those implementations should be preferred in new code.

So replacing all usage of ioutil pkg with io & os.

internal/services/apimanagement/api_management_api_schema_resource_test.go

@@ -3,7 +3,7 @@ package apimanagement_test
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"strings"
 	"testing"
 
@@ -20,7 +20,7 @@ type ApiManagementApiSchemaResource struct{}
 func TestAccApiManagementApiSchema_basic(t *testing.T) {
 	data := acceptance.BuildTestData(t, "azurerm_api_management_api_schema", "test")
 	r := ApiManagementApiSchemaResource{}
-	schema, _ := ioutil.ReadFile("testdata/api_management_api_schema.xml")
+	schema, _ := os.ReadFile("testdata/api_management_api_schema.xml")
 
 	data.ResourceTest(t, r, []acceptance.TestStep{
 		{
@@ -37,7 +37,7 @@ func TestAccApiManagementApiSchema_basic(t *testing.T) {
 func TestAccApiManagementApiSchema_basicSwagger(t *testing.T) {
 	data := acceptance.BuildTestData(t, "azurerm_api_management_api_schema", "test")
 	r := ApiManagementApiSchemaResource{}
-	schema, _ := ioutil.ReadFile("testdata/api_management_api_schema_swagger.json")
+	schema, _ := os.ReadFile("testdata/api_management_api_schema_swagger.json")
 
 	data.ResourceTest(t, r, []acceptance.TestStep{
 		{

internal/services/appservice/helpers/publish_app.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"os"
 	"time"
@@ -182,7 +182,7 @@ func checkZipDeploymentStatusRefresh(r *http.Request) pluginsdk.StateRefreshFunc
 		if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted {
 			return nil, "", fmt.Errorf("failed to read Zip Deployment status: %s", resp.Status)
 		}
-		respBody, err := ioutil.ReadAll(resp.Body)
+		respBody, err := io.ReadAll(resp.Body)
 		if err != nil {
 			return nil, "", fmt.Errorf("reading status response body for Zip Deploy")
 		}

internal/services/storage/storage_account_resource_test.go

@@ -3,7 +3,7 @@ package storage_test
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"regexp"
 	"testing"
@@ -960,7 +960,7 @@ func TestAccAzureRMStorageAccount_sharePropertiesUpdate(t *testing.T) {
 func TestAccAzureRMStorageAccount_shareSoftDelete(t *testing.T) {
 	data := acceptance.BuildTestData(t, "azurerm_storage_account", "test")
 	r := StorageAccountResource{}
-	sourceBlob, err := ioutil.TempFile("", "")
+	sourceBlob, err := os.CreateTemp("", "")
 	if err != nil {
 		t.Fatalf("Failed to create local source blob file")
 	}