Bump xmldom and svg2img

Removes [xmldom](https://github.com/xmldom/xmldom). It's no longer used after updating ancestor dependency [svg2img](https://github.com/fuzhenn/node-svg2img). These dependencies need to be updated together.


Removes `xmldom`

Updates `svg2img` from 0.6.1 to 1.0.0-beta.2
- [Release notes](https://github.com/fuzhenn/node-svg2img/releases)
- [Commits](https://github.com/fuzhenn/node-svg2img/compare/v0.6.1...v1.0.0-beta.2)

---
updated-dependencies:
- dependency-name: xmldom
  dependency-type: indirect
- dependency-name: svg2img
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

README.md

@@ -1,5 +1,6 @@
 [![npm version](https://img.shields.io/npm/v/fa-diagrams.svg)](https://www.npmjs.com/package/fa-diagrams)
 [![Build Status](https://img.shields.io/travis/Klemek/fa-diagrams.svg?branch=master)](https://travis-ci.org/Klemek/fa-diagrams)
+[![Scc Count Badge](https://sloc.xyz/github/klemek/fa-diagrams/?category=code)](https://github.com/boyter/scc/#badges-beta)
 [![Coverage Status](https://img.shields.io/coveralls/github/Klemek/fa-diagrams.svg?branch=master)](https://coveralls.io/github/Klemek/fa-diagrams?branch=master)
 [![Language grade: JavaScript](https://img.shields.io/lgtm/grade/javascript/g/Klemek/fa-diagrams.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/Klemek/fa-diagrams/context:javascript)
 [![Total alerts](https://img.shields.io/lgtm/alerts/g/Klemek/fa-diagrams.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/Klemek/fa-diagrams/alerts/)

package.json

@@ -46,7 +46,7 @@
     "jshint": "^2.10.2",
     "node-svn-ultimate": "^1.2.0",
     "rimraf": "^2.6.3",
-    "svg2img": "^0.6.1",
+    "svg2img": "^1.0.0-beta.2",
     "uglify-es": "^3.3.9"
   }
 }