chore: use deepCopy

[rootulp]

Closes #171

rsmt2d/extendeddatasquare_test.go

Lines 122 to 143 in f166196

	func TestEDSRowColImmutable(t *testing.T) {
	codec := NewLeoRSCodec()
	result, err := ComputeExtendedDataSquare([][]byte{
	ones, twos,
	threes, fours,
	}, codec, NewDefaultTree)
	if err != nil {
	panic(err)
	}
	row := result.Row(0)
	row[0][0]++
	if reflect.DeepEqual(row, result.Row(0)) {
	t.Errorf("Exported EDS Row was mutable")
	}
	col := result.Col(0)
	col[0][0]++
	if reflect.DeepEqual(col, result.Col(0)) {
	t.Errorf("Exported EDS Col was mutable")
	}
	}

still passes

[codecov]

Codecov Report

Merging #175 (73a1c35) into master (6515446) will decrease coverage by 0.33%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #175      +/-   ##
==========================================
- Coverage   81.43%   81.11%   -0.33%     
==========================================
  Files           7        7              
  Lines         528      519       -9     
==========================================
- Hits          430      421       -9     
  Misses         58       58              
  Partials       40       40              

Impacted Files	Coverage Δ
extendeddatasquare.go	73.62% <ø> (-2.38%)	⬇️