Replace deprecated ioutil with io and os

https://pkg.go.dev/io/ioutil is deprecated since Go 1.16.

resources/resource_transformers/babel/babel.go

@@ -17,7 +17,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path"
 	"path/filepath"
@@ -162,7 +161,7 @@ func (t *babelTransformation) Transform(ctx *resources.ResourceTransformationCtx
 	// Create compile into a real temp file:
 	// 1. separate stdout/stderr messages from babel (https://github.com/gohugoio/hugo/issues/8136)
 	// 2. allow generation and retrieval of external source map.
-	compileOutput, err := ioutil.TempFile("", "compileOut-*.js")
+	compileOutput, err := os.CreateTemp("", "compileOut-*.js")
 	if err != nil {
 		return err
 	}
@@ -206,7 +205,7 @@ func (t *babelTransformation) Transform(ctx *resources.ResourceTransformationCtx
 		return fmt.Errorf(errBuf.String()+": %w", err)
 	}
 
-	content, err := ioutil.ReadAll(compileOutput)
+	content, err := io.ReadAll(compileOutput)
 	if err != nil {
 		return err
 	}
@@ -214,7 +213,7 @@ func (t *babelTransformation) Transform(ctx *resources.ResourceTransformationCtx
 	mapFile := compileOutput.Name() + ".map"
 	if _, err := os.Stat(mapFile); err == nil {
 		defer os.Remove(mapFile)
-		sourceMap, err := ioutil.ReadFile(mapFile)
+		sourceMap, err := os.ReadFile(mapFile)
 		if err != nil {
 			return err
 		}

resources/resource_transformers/js/build.go

@@ -15,7 +15,7 @@ package js
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"path"
 	"path/filepath"
@@ -77,7 +77,7 @@ func (t *buildTransformation) Transform(ctx *resources.ResourceTransformationCtx
 		ctx.ReplaceOutPathExtension(".js")
 	}
 
-	src, err := ioutil.ReadAll(ctx.From)
+	src, err := io.ReadAll(ctx.From)
 	if err != nil {
 		return err
 	}
@@ -98,7 +98,7 @@ func (t *buildTransformation) Transform(ctx *resources.ResourceTransformationCtx
 	}
 
 	if buildOptions.Sourcemap == api.SourceMapExternal && buildOptions.Outdir == "" {
-		buildOptions.Outdir, err = ioutil.TempDir(os.TempDir(), "compileOutput")
+		buildOptions.Outdir, err = os.MkdirTemp(os.TempDir(), "compileOutput")
 		if err != nil {
 			return err
 		}

resources/resource_transformers/js/options.go

@@ -16,7 +16,7 @@ package js
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strings"
 
@@ -260,7 +260,7 @@ func createBuildPlugins(c *Client, opts Options) ([]api.Plugin, error) {
 				})
 			build.OnLoad(api.OnLoadOptions{Filter: `.*`, Namespace: nsImportHugo},
 				func(args api.OnLoadArgs) (api.OnLoadResult, error) {
-					b, err := ioutil.ReadFile(args.Path)
+					b, err := os.ReadFile(args.Path)
 					if err != nil {
 						return api.OnLoadResult{}, fmt.Errorf("failed to read %q: %w", args.Path, err)
 					}

resources/resource_transformers/postcss/postcss.go

@@ -19,7 +19,6 @@ import (
 	"encoding/hex"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"path"
 	"path/filepath"
 	"regexp"
@@ -365,7 +364,7 @@ func (imp *importResolver) importRecursive(
 func (imp *importResolver) resolve() (io.Reader, error) {
 	const importIdentifier = "@import"
 
-	content, err := ioutil.ReadAll(imp.r)
+	content, err := io.ReadAll(imp.r)
 	if err != nil {
 		return nil, err
 	}