Upgrade Rust to 1.52.0 (#17096)

* Upgrade Rust to 1.52.0
update nightly_version to newly pushed docker image
fix clippy lint errors
1.52 comes with grcov 0.8.0, include this version to script

* upgrade to Rust 1.52.1

* disabling Serum from downstream projects until it is upgraded to Rust 1.52.1

core/src/sigverify_shreds.rs

@@ -153,7 +153,7 @@ pub mod tests {
         batch[0].packets[1].meta.size = shred.payload.len();
 
         let rv = verifier.verify_batch(batch);
-        assert_eq!(rv[0].packets[0].meta.discard, false);
-        assert_eq!(rv[0].packets[1].meta.discard, true);
+        assert!(!rv[0].packets[0].meta.discard);
+        assert!(rv[0].packets[1].meta.discard);
     }
 }