add quotes around contents of `url()`

[bartveneman]

src: url(/static/notosans-700-italic-9772e36a19092fd2c189c43186fd1bf9.woff2) format("woff2");

should be

src: url("/static/notosans-700-italic-9772e36a19092fd2c189c43186fd1bf9.woff2") format("woff2");