config: Use assert.JSONEq in JSON test

When comparing strings with JSON content, assert.JSONEq is better than
assert.Equal as it will give better output when the 2 strings don't
match, and it tests for equivalence, not strict equality. This means
changes in field order is not a failure for example.

pkg/config/json_test.go

@@ -165,7 +165,7 @@ func testJSON(t *testing.T, test *jsonTest) {
  vm := test.newVM(t)
  data, err := json.Marshal(vm)
  require.NoError(t, err)
- require.Equal(t, test.expectedJSON, string(data))
+ require.JSONEq(t, test.expectedJSON, string(data))
 
  var unmarshalledVM VirtualMachine
  err = json.Unmarshal([]byte(test.expectedJSON), &unmarshalledVM)