Tuya rgb support (#2278)

Co-authored-by: Oxan van Leeuwen <oxan@oxanvanleeuwen.nl>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/core/helpers.h

@@ -43,7 +43,8 @@ std::string to_string(double val);
 std::string to_string(long double val);
 optional<float> parse_float(const std::string &str);
 optional<int> parse_int(const std::string &str);
-
+optional<int> parse_hex(const std::string &str, size_t start, size_t length);
+optional<int> parse_hex(char chr);
 /// Sanitize the hostname by removing characters that are not in the allowlist and truncating it to 63 chars.
 std::string sanitize_hostname(const std::string &hostname);