fix: update error message

Author: kgryte

lib/node_modules/@stdlib/blas/tools/swap-factory/lib/main.js

@@ -71,7 +71,7 @@ function factory( base, dtype ) {
 		throw new TypeError( format( 'invalid argument. First argument must be a function. Value: `%s`.', base ) );
 	}
 	if ( !isDataType( dtype ) && dtype !== null ) {
-		throw new TypeError( format( 'invalid argument. Second argument must a data type. Value: `%s`.', dtype ) );
+		throw new TypeError( format( 'invalid argument. Second argument must be a data type. Value: `%s`.', dtype ) );
 	}
 	isValid = ( dtype ) ? isValidWrapper : isndarrayLike;
 	return swap;