rust 1.53.0 updates (#2411)

## Issue Addressed

`make lint` failing on rust 1.53.0.

## Proposed Changes

1.53.0 updates

## Additional Info

I haven't figure out why yet, we were now hitting the recursion limit in a few crates. So I had to add `#![recursion_limit = "256"]` in a few places


Co-authored-by: realbigsean <seananderson33@gmail.com>
Co-authored-by: Michael Sproul <michael@sigmaprime.io>

slasher/src/block_queue.rs

@@ -13,7 +13,7 @@ impl BlockQueue {
 
     pub fn dequeue(&self) -> Vec<SignedBeaconBlockHeader> {
         let mut blocks = self.blocks.lock();
-        std::mem::replace(&mut *blocks, vec![])
+        std::mem::take(&mut *blocks)
     }
 
     pub fn len(&self) -> usize {