all: use %w instead of %v to wrap errors (#1275)

* all: use %w instead of %v for nested errors with fmt.Errorf

* all: update generated code to use %w instead of %v for error wrapping

entc/gen/template/dialect/sql/tx.tmpl

@@ -14,7 +14,7 @@ func (c *Client) BeginTx(ctx context.Context, opts *sql.TxOptions) (*Tx, error)
 		BeginTx(context.Context, *sql.TxOptions) (dialect.Tx, error)
 	}).BeginTx(ctx, opts)
 	if err != nil {
-		return nil, fmt.Errorf("ent: starting a transaction: %v", err)
+		return nil, fmt.Errorf("ent: starting a transaction: %w", err)
 	}
 	cfg := c.config
 	cfg.driver = &txDriver{tx: tx, drv: c.driver}