Add CI and badges

Author: slevithan

.github/workflows/main.yml

@@ -0,0 +1,21 @@
+name: CI
+on:
+  - push
+  - pull_request
+jobs:
+  test:
+    name: Node.js ${{ matrix.node-version }}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version:
+          - 20
+          - 14
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+      - run: npm install
+      - run: npm test

README.md

@@ -1,5 +1,9 @@
 # regex-utilities
 
+[![build status](https://github.com/slevithan/regex-utilities/workflows/CI/badge.svg)](https://github.com/slevithan/regex-utilities/actions)
+[![npm](https://img.shields.io/npm/v/regex-utilities)](https://www.npmjs.com/package/regex-utilities)
+[![bundle size](https://deno.bundlejs.com/badge?q=regex-utilities&treeshake=[*])](https://bundlejs.com/?q=regex-utilities&treeshake=[*])
+
 Tiny utilities shared by the [`regex`](https://github.com/slevithan/regex) library and its extensions. Useful for parsing and processing regular expressions, when you don't need a full regex AST builder.
 
 ## Constants