Folks using a unix socket could use /run/miniflux/miniflux.sock without permission issue

The miniflux user is not created on new installations

Some websites redirects unknown URLs to the home page.
As result, the list of known URLs is returned to the subscription list.
We don't want the user to choose between invalid feed URLs.

This ensures that the relevant port is published when using `docker run -P`, Traefik's Docker integration etc

Avoid encoding single quotes to HTML entities (').

Feed contents are sanitized after parsing.

The default transport was changed in commit 0d66f2c6 and the proxy feature was forgotten.

- https://golang.org/src/net/http/transport.go#L43
- https://golang.org/pkg/net/http/#ProxyFromEnvironment

Avoid looping multiple times across entries

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.7.1 to 1.8.0.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/master/CHANGELOG.md)
- [Commits](https://github.com/prometheus/client_golang/compare/v1.7.1...v1.8.0

)

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

Bumps [github.com/PuerkitoBio/goquery](https://github.com/PuerkitoBio/goquery) from 1.5.1 to 1.6.0.
- [Release notes](https://github.com/PuerkitoBio/goquery/releases)
- [Commits](https://github.com/PuerkitoBio/goquery/compare/v1.5.1...v1.6.0

)

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

- Add support for picture HTML tag
- Add support for srcset, media, and sizes attributes to img and source tags