GHSA-f3qr-qr4x-j273

### Summary php-svg-lib fails to validate that font-family doesn't contain a PHAR url, which might leads to RCE on PHP < 8.0, and doesn't validate if external references are allowed. This might leads to bypass of restrictions or RCE on projects that are using it, if they do not strictly revalidate the fontName that is passed by php-svg-lib.

### Details The Style::fromAttributes(), or the Style::parseCssStyle() should check the content of the `font-family` and prevents it to use a PHAR url, to avoid passing an invalid and dangerous `fontName` value to other libraries. The same check as done in the Style::fromStyleSheets might be reused :

``` if ( \array_key_exists("font-family", $styles) && ( \strtolower(\substr($this->href, 0, 7)) === "phar://" || ($this->document->allowExternalReferences === false && \strtolower(\substr($this->href, 0, 5)) !== "data:") ) ) { unset($style["font-family"]); } ```

### PoC

Parsing the following SVG :

``` <?xml version="1.0" encoding="UTF-8" standalone="no"?> <svg xmlns:svg="http://www.w3.org/2000/svg" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="200" height="200"> <text x="20" y="35" style="color:red;font-family:phar:///path/to/whatever.phar/blaklis;">My</text> </svg> ```

will pass the `phar:///path/to/whatever.phar/blaklis` as `$family` in `SurfaceCpdf::setFont`, which is then passed to the canvas `selectFont` as a `$fontName`.

### Impact Libraries using this library as a dependency might be vulnerable to some bypass of restrictions, or even RCE, if they do not double check the value of the `fontName` that is passed by php-svg-lib