build(deps): bump html2rss in the rubygems group

Bumps the rubygems group with 1 update: [html2rss](https://github.com/html2rss/html2rss).


Updates `html2rss` from `c30d3e3` to `6504069`
- [Release notes](https://github.com/html2rss/html2rss/releases)
- [Commits](html2rss/html2rss@c30d3e3...6504069)

---
updated-dependencies:
- dependency-name: html2rss
  dependency-version: 6504069845c54286cb4b5032bc1deb01fed9a0eb
  dependency-type: direct:production
  dependency-group: rubygems
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -1,6 +1,6 @@
 GIT
   remote: https://github.com/html2rss/html2rss
-  revision: c30d3e397b7cde23f41758b9619bdc274edfd815
+  revision: 6504069845c54286cb4b5032bc1deb01fed9a0eb
   branch: master
   specs:
     html2rss (0.17.0)