Fix build and update README badges

Author: runarberg

.github/workflows/ci.yml

@@ -44,7 +44,7 @@ jobs:
         run: npm ci
 
       - name: Test
-        run: npm run test:coverage
+        run: npm run test
 
   lint:
     runs-on: ubuntu-latest

README.md

@@ -1,5 +1,8 @@
+[![ci](https://github.com/runarberg/markdown-it-math/actions/workflows/ci.yml/badge.svg)](https://github.com/runarberg/markdown-it-math/actions/workflows/ci.yml)
+![Coverage](https://runarberg.github.io/markdown-it-math/badge.svg)
 [![npm](https://img.shields.io/npm/v/markdown-it-math.svg)](https://www.npmjs.com/package/markdown-it-math)
-[![Build Status](https://travis-ci.org/runarberg/markdown-it-math.svg?branch=master)](https://travis-ci.org/runarberg/markdown-it-math)
+[![License](https://img.shields.io/npm/l/markdown-it-math)](https://github.com/runarberg/markdown-it-math/blob/main/LICENSE)
+[![Downloads](https://img.shields.io/npm/dm/markdown-it-math)](https://npm-stat.com/charts.html?package=markdown-it-math)
 
 **Note:** This is a general [markdown-it][markdown-it] math plugin. It
 was originally designed to render [MathML][mathml]. If you intend to