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/opendrive/opendrive.go

@@ -2,6 +2,7 @@ package opendrive
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -11,7 +12,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/pkg/errors"
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config"
 	"github.com/rclone/rclone/fs/config/configmap"
@@ -210,7 +210,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 		return f.shouldRetry(ctx, resp, err)
 	})
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to create session")
+		return nil, fmt.Errorf("failed to create session: %w", err)
 	}
 	fs.Debugf(nil, "Starting OpenDrive session with ID: %s", f.session.SessionID)
 
@@ -362,7 +362,7 @@ func (f *Fs) Copy(ctx context.Context, src fs.Object, remote string) (fs.Object,
 	srcPath := srcObj.fs.rootSlash() + srcObj.remote
 	dstPath := f.rootSlash() + remote
 	if strings.ToLower(srcPath) == strings.ToLower(dstPath) {
-		return nil, errors.Errorf("Can't copy %q -> %q as are same name when lowercase", srcPath, dstPath)
+		return nil, fmt.Errorf("Can't copy %q -> %q as are same name when lowercase", srcPath, dstPath)
 	}
 
 	// Create temporary object
@@ -636,7 +636,7 @@ func (f *Fs) Put(ctx context.Context, in io.Reader, src fs.ObjectInfo, options .
 			return o.fs.shouldRetry(ctx, resp, err)
 		})
 		if err != nil {
-			return nil, errors.Wrap(err, "failed to create file")
+			return nil, fmt.Errorf("failed to create file: %w", err)
 		}
 
 		o.id = response.FileID
@@ -719,7 +719,7 @@ func (f *Fs) FindLeaf(ctx context.Context, pathID, leaf string) (pathIDOut strin
 		return f.shouldRetry(ctx, resp, err)
 	})
 	if err != nil {
-		return "", false, errors.Wrap(err, "failed to get folder list")
+		return "", false, fmt.Errorf("failed to get folder list: %w", err)
 	}
 
 	leaf = f.opt.Enc.FromStandardName(leaf)
@@ -762,7 +762,7 @@ func (f *Fs) List(ctx context.Context, dir string) (entries fs.DirEntries, err e
 		return f.shouldRetry(ctx, resp, err)
 	})
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to get folder list")
+		return nil, fmt.Errorf("failed to get folder list: %w", err)
 	}
 
 	for _, folder := range folderList.Folders {
@@ -871,7 +871,7 @@ func (o *Object) Open(ctx context.Context, options ...fs.OpenOption) (in io.Read
 		return o.fs.shouldRetry(ctx, resp, err)
 	})
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to open file)")
+		return nil, fmt.Errorf("failed to open file): %w", err)
 	}
 
 	return resp.Body, nil
@@ -919,7 +919,7 @@ func (o *Object) Update(ctx context.Context, in io.Reader, src fs.ObjectInfo, op
 		return o.fs.shouldRetry(ctx, resp, err)
 	})
 	if err != nil {
-		return errors.Wrap(err, "failed to create file")
+		return fmt.Errorf("failed to create file: %w", err)
 	}
 	// resp.Body.Close()
 	// fs.Debugf(nil, "PostOpen: %#v", openResponse)
@@ -963,10 +963,10 @@ func (o *Object) Update(ctx context.Context, in io.Reader, src fs.ObjectInfo, op
 			return o.fs.shouldRetry(ctx, resp, err)
 		})
 		if err != nil {
-			return errors.Wrap(err, "failed to create file")
+			return fmt.Errorf("failed to create file: %w", err)
 		}
 		if reply.TotalWritten != currentChunkSize {
-			return errors.Errorf("failed to create file: incomplete write of %d/%d bytes", reply.TotalWritten, currentChunkSize)
+			return fmt.Errorf("failed to create file: incomplete write of %d/%d bytes", reply.TotalWritten, currentChunkSize)
 		}
 
 		chunkCounter++
@@ -986,7 +986,7 @@ func (o *Object) Update(ctx context.Context, in io.Reader, src fs.ObjectInfo, op
 		return o.fs.shouldRetry(ctx, resp, err)
 	})
 	if err != nil {
-		return errors.Wrap(err, "failed to create file")
+		return fmt.Errorf("failed to create file: %w", err)
 	}
 	// fs.Debugf(nil, "PostClose: %#v", closeResponse)
 
@@ -1038,7 +1038,7 @@ func (o *Object) readMetaData(ctx context.Context) (err error) {
 		return o.fs.shouldRetry(ctx, resp, err)
 	})
 	if err != nil {
-		return errors.Wrap(err, "failed to get folder list")
+		return fmt.Errorf("failed to get folder list: %w", err)
 	}
 
 	if len(folderList.Files) == 0 {