message: Fix: `purser-metamask` signMessage static method unit tests
diff: @@ -38,11 +38,13 @@ jest.mock('@colony/purser-metamask/helpers', () =>
  const mockedMessageSignature = 'mocked-message-signature';
  const callbackError = { message: 'no-error-here' };
  global.web3 = {
  + eth: {
  personal: {
  sign: jest.fn((message, address, callback) =>
  callback(callbackError, mockedMessageSignature),
  ),
  },
  + },
  };
  /*
  * Mock the Buffer global object
  @@ -69,7 +71,7 @@ const mockedArgumentsObject = {
  describe('`Metamask` Wallet Module Static Methods', () => {
  afterEach(() => {
  - global.web3.personal.sign.mockClear();
  + global.web3.eth.personal.sign.mockClear();
  global.Buffer.from.mockClear();
  methodCaller.mockClear();
  addressValidator.mockClear();
  @@ -81,8 +83,8 @@ describe('`Metamask` Wallet Module Static Methods', () => {
  describe('`signMessage()` static method', () => {
  test('Calls the correct metamask injected method', async () => {
  await signMessage(mockedArgumentsObject);
  - expect(global.web3.personal.sign).toHaveBeenCalled();
  - expect(global.web3.personal.sign).toHaveBeenCalledWith(
  + expect(global.web3.eth.personal.sign).toHaveBeenCalled();
  + expect(global.web3.eth.personal.sign).toHaveBeenCalledWith(
  mockedMessage,
  mockedAddress,
  expect.any(Function),
  @@ -170,7 +172,7 @@ describe('`Metamask` Wallet Module Static Methods', () => {
  hexSequenceValidator.mockImplementation(() => {
  throw new Error();
  });
  - global.web3.personal.sign.mockImplementation(
  + global.web3.eth.personal.sign.mockImplementation(
  (message, address, callback) =>
  callback(
  { ...callbackError, message: STD_ERRORS.CANCEL_MSG_SIGN },
  