v0.6.0

• Upgraded to a more recent version of itertools. This caused a name collision between the new get function on the Itertools traits and various get functions on some iterators in Malachite. To resolve this, the Malachite functions were renamed to get_digit or get_limb, depending on the iterator. This is a breaking change.
• Thanks to coolreader18 for removing a transitive dependency on the syn crate in malachite-bigint.
• Thanks to twizmwazin for updating the pyo3 version.
• Various improvements caught by Clippy.