Remove github.com/pkg/errors and replace with std library version

This is possible now that we no longer support go1.12 and brings
rclone into line with standard practices in the Go world.

This also removes errors.New and errors.Errorf from lib/errors and
prefers the stdlib errors package over lib/errors.

backend/tardigrade/fs.go

@@ -6,13 +6,13 @@ package tardigrade
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"path"
 	"strings"
 	"time"
 
-	"github.com/pkg/errors"
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config"
 	"github.com/rclone/rclone/fs/config/configmap"
@@ -64,12 +64,12 @@ func init() {
 
 				access, err := uplink.RequestAccessWithPassphrase(context.TODO(), satellite, apiKey, passphrase)
 				if err != nil {
-					return nil, errors.Wrap(err, "couldn't create access grant")
+					return nil, fmt.Errorf("couldn't create access grant: %w", err)
 				}
 
 				serializedAccess, err := access.Serialize()
 				if err != nil {
-					return nil, errors.Wrap(err, "couldn't serialize access grant")
+					return nil, fmt.Errorf("couldn't serialize access grant: %w", err)
 				}
 				m.Set("satellite_address", satellite)
 				m.Set("access_grant", serializedAccess)
@@ -78,7 +78,7 @@ func init() {
 				config.FileDeleteKey(name, "api_key")
 				config.FileDeleteKey(name, "passphrase")
 			} else {
-				return nil, errors.Errorf("invalid provider type: %s", provider)
+				return nil, fmt.Errorf("invalid provider type: %s", provider)
 			}
 			return nil, nil
 		},
@@ -188,24 +188,24 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (_ fs.Fs,
 	if f.opts.Access != "" {
 		access, err = uplink.ParseAccess(f.opts.Access)
 		if err != nil {
-			return nil, errors.Wrap(err, "tardigrade: access")
+			return nil, fmt.Errorf("tardigrade: access: %w", err)
 		}
 	}
 
 	if access == nil && f.opts.SatelliteAddress != "" && f.opts.APIKey != "" && f.opts.Passphrase != "" {
 		access, err = uplink.RequestAccessWithPassphrase(ctx, f.opts.SatelliteAddress, f.opts.APIKey, f.opts.Passphrase)
 		if err != nil {
-			return nil, errors.Wrap(err, "tardigrade: access")
+			return nil, fmt.Errorf("tardigrade: access: %w", err)
 		}
 
 		serializedAccess, err := access.Serialize()
 		if err != nil {
-			return nil, errors.Wrap(err, "tardigrade: access")
+			return nil, fmt.Errorf("tardigrade: access: %w", err)
 		}
 
 		err = config.SetValueAndSave(f.name, "access_grant", serializedAccess)
 		if err != nil {
-			return nil, errors.Wrap(err, "tardigrade: access")
+			return nil, fmt.Errorf("tardigrade: access: %w", err)
 		}
 	}
 
@@ -237,7 +237,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (_ fs.Fs,
 		if bucketName != "" && bucketPath != "" {
 			_, err = project.StatBucket(ctx, bucketName)
 			if err != nil {
-				return f, errors.Wrap(err, "tardigrade: bucket")
+				return f, fmt.Errorf("tardigrade: bucket: %w", err)
 			}
 
 			object, err := project.StatObject(ctx, bucketName, bucketPath)
@@ -274,7 +274,7 @@ func (f *Fs) connect(ctx context.Context) (project *uplink.Project, err error) {
 
 	project, err = cfg.OpenProject(ctx, f.access)
 	if err != nil {
-		return nil, errors.Wrap(err, "tardigrade: project")
+		return nil, fmt.Errorf("tardigrade: project: %w", err)
 	}
 
 	return