correct information about packages in readme

[milyin]

Describe the release item

This piece of information:

There are two kind of packages:

    libzenohpico: only contains the library file (.so)
    libzenohpico-dev: contains the zenoh-pico header files for development and depends on the libzenohpico package

is not valid since zenoh 0.5 beta 8. Compare:
https://download.eclipse.org/zenoh/zenoh-pico/0.5.0-beta.8/
and
https://download.eclipse.org/zenoh/zenoh-pico/1.1.0/

Maybe it's better to just remove this section

[milyin]

Correction after consultation with @sashacmc : the libzenohpico and libzenohpico-dev are package names inside the archives. So the readme is technically correct, though maybe not fully clear