Fix clippy warning about eliding explicit lifetime

Clippy produces a warning:

    warning: the following explicit lifetimes could be elided: 'a
       --> src/main.rs:351:17
        |
    351 |     fn get_data<'a>(&'a self) -> Self::Data<'a> {
        |                 ^^   ^^                     ^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
        = note: `#[warn(clippy::needless_lifetimes)]` on by default
    help: elide the lifetimes
        |
    351 -     fn get_data<'a>(&'a self) -> Self::Data<'a> {
    351 +     fn get_data(&self) -> Self::Data<'_> {
        |

Fix the warning by following the advice from clippy.

Signed-off-by: Christopher Obbard <[email protected]>

src/main.rs

@@ -348,7 +348,7 @@ impl UploadableFile for LavaUploadableFile {
         }
     }
 
-    fn get_data<'a>(&'a self) -> Self::Data<'a> {
+    fn get_data(&self) -> Self::Data<'_> {
         outputln!("Uploading {}", self.get_path());
         match &self.which {
             LavaUploadableFileType::Log { id } => {