patch dependencies and fix imports (#167)

Co-authored-by: Pratyush Mishra <pratyushmishra@berkeley.edu>

bls12_381/src/fields/tests.rs

@@ -1,9 +1,8 @@
 use ark_algebra_test_templates::*;
-use ark_ec::AdditiveGroup;
 use ark_ff::{
     biginteger::{BigInt, BigInteger, BigInteger384},
     fields::{FftField, Field, Fp12Config, Fp2Config, Fp6Config, PrimeField},
-    One, UniformRand, Zero,
+    AdditiveGroup, One, UniformRand, Zero,
 };
 use ark_std::{
     cmp::Ordering,