micromark crashes on invalid URI

[ChristianMurphy]

Subject of the issue

Some malformed URL can crash micromark

Your environment

• OS: Ubuntu 16
• Packages: micromark 2.6.0
• Env: Node 14

Steps to reproduce

var micromark = require('micromark')

console.log(micromark('[](<%>)'))

originally detected with #18, credit to @wooorm for a more minimal repro

Expected behavior

<p><a href="%25"></a></p>

Actual behavior

URIError: URI malformed
    at decodeURI (<anonymous>)
    at normalizeUri (micromark/dist/util/normalize-uri.js:1:1040)
    at url (micromark/dist/compile/html.js:1:54303)
    at Object.onexitmedia (micromark/dist/compile/html.js:1:61812)
    at done (micromark/dist/compile/html.js:1:50389)
    at compile (micromark/dist/compile/html.js:1:48534)
    at buffer (micromark/dist/index.js:1:2192)
    at Worker.fuzz [as fn] (micromark/fuzzer.js:1:1781)
    at process.<anonymous> (micromark/node_modules/jsfuzz/build/src/worker.js:63:30)

[wooorm]

Well, that was an interesting deep-dive into uris! Fixed!