Upgrade minimum reqiured version of Rust to 1.29

[sharkdp]

This upgrades the minimum required version of Rust to 1.29 in order to fix #916 (Zombie processes cause rg --files to hang in /proc).

I have manually confirmed that the bug is fixed when compiling ripgrep with 1.29.

It's probably better to merge this just before the next release in order for the current Rust version to still be in present in the README(?).

See also:

• Rust compiler bug ticket: fs::read_dir iterator loops forever on same entry rust-lang/rust#50619
• Rust compiler PR with the fix: Fix possibly endless loop in ReadDir iterator rust-lang/rust#50630

closes #916

[BurntSushi]

It's probably better to merge this just before the next release in order for the current Rust version to still be in present in the README(?).

Ah right yeah. Basically, to keep things sensible, I'd like to make sure any 0.x.y releases build on the same version as the 0.x.0 release. So I won't bump the minimum Rust version until I know the next release is 0.11.

I will just do that as part of the normal release process, so I'm going to close this. In theory, it could be months before a 0.11 release. :) Thank you for the reminder though and staying on top of this!

[sharkdp]

I'd like to make sure any 0.x.y releases build on the same version as the 0.x.0 release

Ah, that makes sense.

In theory, it could be months before a 0.11 release.

ripgrep 0.10 was six days early 😄