Ignore needless_lifetimes clippy lint

    warning: the following explicit lifetimes could be elided: 'a
      --> src/matrix.rs:67:6
       |
    67 | impl<'a> DoubleEndedIterator for Iter<'a> {
       |      ^^                               ^^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
       = note: `-W clippy::needless-lifetimes` implied by `-W clippy::all`
       = help: to override `-W clippy::all` add `#[allow(clippy::needless_lifetimes)]`
    help: elide the lifetimes
       |
    67 - impl<'a> DoubleEndedIterator for Iter<'a> {
    67 + impl DoubleEndedIterator for Iter<'_> {
       |

    warning: the following explicit lifetimes could be elided: 'a
       --> src/matrix.rs:122:6
        |
    122 | impl<'a> Debug for RelativeRow<'a> {
        |      ^^                        ^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
    help: elide the lifetimes
        |
    122 - impl<'a> Debug for RelativeRow<'a> {
    122 + impl Debug for RelativeRow<'_> {
        |

src/lib.rs

@@ -17,6 +17,7 @@
     clippy::missing_panics_doc,
     clippy::module_name_repetitions,
     clippy::must_use_candidate,
+    clippy::needless_lifetimes,
     clippy::needless_pass_by_value,
     clippy::ptr_as_ptr,
     clippy::significant_drop_in_scrutinee,