feat!: update to eslint v9, flat config only (#8)

* feat!: update to eslint v9, flat config only

BREAKING CHANGE: This package now only exports flat config. For more information see the [eslint migration guide](https://eslint.org/blog/2024/04/eslint-v9.0.0-released) and [flat config guide](https://eslint.org/blog/2022/08/new-config-system-part-2/). The README of this package has instructions for how to use this package with the new flat config system.

* refactor: write code in TS and compile with tsup

* fix: add an `index.ts` that re-exports other configs

* docs: update README

* fix: add the missing require export mapping

* chore: cleanup dev deps

* ci: add continuous integration workflow

* feat: update all configs to v9, with compat where needed

* chore: cleanup code for fix-tsup-type-files

* build: add script to generate src/index.ts

* build: disable tsup bundling

* style: formatting

* fix: properly enable import-x and re-enable promise/ and sonarjs/ rules

* fix: add `esbuild-plugin-file-path-extensions` to ensure proper CJS and MJS extensions

* fix: fix deprecated angular rules

* docs(readme): fixup angular usage

* docs(angular): use `lodash.merge`

* docs: formatting

* feat: add react-refresh

* fix: use eslint-plugin-prettier instead of eslint-config-prettier

* fix: disable `unicorn/consistent-function-scoping` for jsx/react

.github/workflows/continuous-integration.yml

@@ -0,0 +1,52 @@
+name: Continuous Integration
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+jobs:
+  build-and-lint:
+    name: Build & Lint
+    runs-on: ubuntu-latest
+    if: github.repository_owner == 'icrawl'
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Use Node.js v20
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install Dependencies
+        run: yarn --immutable
+
+      - name: Build & Lint
+        run: yarn lint
+
+  validate-generated-index:
+    name: Validate Generated Index
+    runs-on: ubuntu-latest
+    if: github.repository_owner == 'icrawl'
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Use Node.js v20
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install Dependencies
+        run: yarn --immutable
+
+      - name: Generate new index
+        run: yarn gen-index
+
+      - name: Error if index is different
+        run: |
+          git status
+          if ! git diff-index --quiet HEAD --; then
+            echo "::error file=src/index.ts::File did not match generated file after script. Please review and adjust accordingly."
+            exit 1;
+          fi