Add .dup on an empty string to get an non-frozen option

lib/github/sql.rb

@@ -152,7 +152,7 @@ def initialize(query = nil, binds = nil)
  @last_insert_id = nil
  @affected_rows = nil
  @binds = binds ? binds.dup : {}
- @query = ""
+ @query = "".dup
  @connection = @binds.delete :connection
  @force_timezone = @binds.delete :force_timezone