* Add @testing-library/jest-dom and @testing-library/react for writing test cases
* Make eslint check __mocks__/*.ts files
* Mock electron.ipcRenderer.on to prevent errors in React compoment test cases
* Mock <Trans /> from @lingui/macro as a component simplely returns children components
* Use optional chaining operator (?.) to avoid TypeError: Cannot read property 'replicas' of undefined
* Add jest-fetch-mock for mocking global.fetch, activate for all test cases in jest.setup.ts
* Add basic tests for <DeploymentScaleDialog /> to ensure it initialises/renders without errors
* Add +/- button for changing desired replicas, and its test cases
* Adjust the styles of +/- buttons container to make sure it aligns with the slider
* Refactor after rebase from master
* Use var defined in vars.scss
* Add flex align-center to slider-container and remove margin-top: -4px
* Use <Icon /> to replace <i/>
* Add flex gaps to plus-minus-container
Signed-off-by: Hung-Han (Henry) Chen <1474479+chenhunghan@users.noreply.github.com>
