bump toolchain version

[IceSentry]

This is in preparation for migrating to bevy 0.11 since it needs rust 1.70

[github-actions]

bevy-aabb-instancing - ✅ bevy-aabb-instancing

required	step	result	details
✓	Custom:	⏭	Logs
✓	cargo fmt --verbose --all -- --check	✅	Logs
✓	cargo check	✅	Logs
✓	cargo clippy -- -D warnings	✅	Logs
	cargo doc	✅	Logs
	cargo deny check licenses	✅	Logs
	cargo deny check bans	✅	Logs
	cargo deny check advisories	✅	Logs
	cargo deny check sources	✅	Logs
	cargo machete	✅	Logs
✓	cargo test	✅	Logs
	cargo miri test	⏭	Logs
✓	cargo publish --dry-run	✅	Logs

Pushed by: IceSentry, Action: pull_request;
Run: 6410273287
Logs: Logs