cli: switch to v8 coverage provider

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/giant-bees-applaud.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Switch the default test coverage provider from the jest default one to `'v8'`, which provides much better coverage information when using the default Backstage test setup. This is considered a bug fix as the current coverage information is often very inaccurate.

packages/cli/config/jest.js

@@ -95,6 +95,7 @@ async function getProjectConfig(targetPath, displayName) {
     ...(displayName && { displayName }),
     rootDir: path.resolve(targetPath, 'src'),
     coverageDirectory: path.resolve(targetPath, 'coverage'),
+    coverageProvider: 'v8',
     collectCoverageFrom: ['**/*.{js,jsx,ts,tsx}', '!**/*.d.ts'],
     moduleNameMapper: {
       '\\.(css|less|scss|sss|styl)$': require.resolve('jest-css-modules'),