refactor: move from io/ioutil to io and os package

The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

connector/atlassiancrowd/atlassiancrowd.go

@@ -7,7 +7,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"strings"
@@ -432,7 +431,7 @@ func (c *crowdConnector) crowdUserManagementRequest(ctx context.Context, method
 
 // validateCrowdResponse validates unique not JSON responses from API
 func (c *crowdConnector) validateCrowdResponse(resp *http.Response) ([]byte, error) {
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return nil, fmt.Errorf("crowd: read user body: %v", err)
 	}