updated type of treat_first_row_as_header

proto/substrait/algebra.proto

@@ -153,7 +153,7 @@ message ReadRel {
         uint64 skip_lines = 4;
         // If true, consume the first unskipped line as names of the columns.
         // These names are not used elsewhere in the plan.
-        uint64 treat_first_row_as_header = 5;
+        bool treat_first_row_as_header = 5;
         // The character used to escape characters in strings.  Backslash is
         // a common value.  Note that a double quote mark can also be used as an
         // escape character but the external quotes should be removed first.