finance/ledger: unbreak with boost 1.68

In file included from src/generate.cc:34:
In file included from src/generate.h:45:
In file included from src/iterators.h:45:
In file included from src/xact.h:45:
In file included from src/item.h:45:
In file included from src/scope.h:45:
In file included from src/op.h:45:
In file included from src/expr.h:45:
In file included from src/exprbase.h:57:
src/utils.h:47:10: fatal error: 'boost/uuid/sha1.hpp' file not found
#include <boost/uuid/sha1.hpp>

^

PR: 229569