feat: umi-immer

[sorrycc]

Close #1587

e.g.

export default {
  namespace: 'count',
  state: {
    a: {
      b: {
        c: {
          count: 0,
        },
      },
    },
  },
  reducers: {
    add(state) {
      state.a.b.c.count += 1;
    },
  },
};

[coveralls]

Coverage decreased (-1.2%) to 68.653% when pulling db994da on feat/dva-immer into 6787ae9 on master.

[coveralls]

Coverage increased (+0.6%) to 70.419% when pulling 1868cd7 on feat/dva-immer into 6787ae9 on master.

[paranoidjk]

👍 LGTM