cync_lan (Home Assistant custom_component) v2.5.3

Documentation only - no code change.

The comparison table on the repository's front page still said this integration
"is not on the default branch yet, which makes HACS installation more manual for
now". That stopped being true when feature/ha-custom-component became the
default branch; HACS installs work like any other custom repository. The
integration's own README and RELEASING.md were corrected at the time and this
line was missed.

Released rather than left to sit on the branch because HACS installs the latest
release, so until now the copy users actually got was the one still telling them
the install path was awkward.