rustler-0.29.0

What's Changed

• Make rustler_sys forward compatible by @filmor in #536
• Add OTP26 to CI and bump rustler_sys by @filmor in #539
• Introduce CI cache by @filmor in #541
• Drop OTP23 entirely from CI and use -latest for all OS versions by @filmor in #542
• Use features for minimal NIF version by @filmor in #537
• Apply current NIF version for tests and raise default by @filmor in #543
• rustler: add a Rust type ErlOption<T> by @tatsuya6502 in #507

Full Changelog: rustler-0.28.0...rustler-0.29.0