#196 - Fix to failing unit tests

[speedytwenty]

This mocks the colors module within the "legacy tests" to produce consistent output from colors—as the tests expect.

This one-liner appropriately resolves #196.

[speedytwenty]

To emphasize, this failing test is not detected by CI (Travis nor Github Actions) but only by developers.

To verify this fix requires testing both the failing test and the passing test manually:

➭ git clone https://github.com/speedytwenty/cli-table3.git
➭ cd cli-table3
➭ yarn install --frozen-lockfile
➭ yarn test
➭ git checkout issue-196b
➭ yarn test

Use ➭ git checkout v0.6.0 to see the tests fail if testing after the fix hits master.