OSV-2020-734 Heap-buffer-overflow in Sass::Prelexer::quoted_string

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=15890 Crash type: Heap-buffer-overflow READ 1 Crash state: Sass::Prelexer::quotedstring char const Sass::Parser::lex& Sass::Parser::parsevalueschema...