When using "base" in dojo.rc, references to webfonts in /assets are not adjusted

**Bug**

When you use the base property in .dojorc to change the base path to, for example, "/admin/" instead of "/", the generated index.html will be changed properly to reflect that. However, webfont references to locally hosted web fonts (in assets directory) are not changed - they stay at "/assets/". At runtime, the browser will reference /assets/xxx.woff instead of /admin/assets/xx.woff and will not find the webfont. Interestingly, when hosted by the dojo --serve --watch mechanism, this works. When using a production build and moving the content of the list directory to an http server, it doesn't - 404 not finding the resource. All css and js resources are resolved properly.

To be honest I am not entirely why this doesnt work. Creating this issue as discussed in Discord.

Package Version: 7.0.0

**Code**
[hello-world-webfont.zip](https://github.com/dojo/cli/files/5973556/hello-world-webfont.zip)

Sample based on the default hello world app, with only minimum modifications:
- add webfont
- reference webfont in css and set style of Home.m.css to use it
- set base in .dojorc to /admin/

**Expected behavior:**

Webfont should be loaded.

**Actual behavior:**

Webfont is not loaded because the browser tries to load the font from /assets instead of /admin/assets