refactor: move from io/ioutil to io and os package (#2236)

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>

pkg/builder/builder.go

@@ -21,7 +21,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"os/exec"
@@ -98,7 +97,7 @@ func (builder *Builder) Handler(w http.ResponseWriter, r *http.Request) {
 	}()
 
 	// parse request
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		e := "error reading request body"
 		builder.logger.Error(e, zap.Error(err))

pkg/builder/client/client.go

@@ -20,7 +20,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"strings"
 	"time"
@@ -31,7 +31,7 @@ import (
 	"go.uber.org/zap"
 	"golang.org/x/net/context/ctxhttp"
 
-	builder "github.com/fission/fission/pkg/builder"
+	"github.com/fission/fission/pkg/builder"
 	ferror "github.com/fission/fission/pkg/error"
 	otelUtils "github.com/fission/fission/pkg/utils/otel"
 	"github.com/fission/fission/pkg/utils/tracing"
@@ -91,7 +91,7 @@ func (c *Client) Build(ctx context.Context, req *builder.PackageBuildRequest) (*
 
 	defer resp.Body.Close()
 
-	rBody, err := ioutil.ReadAll(resp.Body)
+	rBody, err := io.ReadAll(resp.Body)
 	if err != nil {
 		logger.Error("error reading resp body", zap.Error(err))
 		return nil, err