The last public detailed instructions for using the SWI-Prolog package library rocks-predicates on Ubuntu that I posted is here
This did not use
pack_install('https://github.com/JanWielemaker/rocks-predicates.git').
but instead
git clone https://github.com/JanWielemaker/rocks-predicates.git
Now that I just reread the posted instructions from many months ago I did not use that as it probably did not work then either as it is a library and not a package.
Here is where using pack_install/1 with a Git URL did work as expected.
?- pack_install('https://github.com/JanWielemaker/rocksdb.git').