This only works for packages published to mops.
Try this to install from github:
mops add https://github.com/ZhenyaUsenko/motoko-hash-map#v7.0.0
and import like this
import Map "mo:motoko-hash-map/Map";
Also you can rename motoko-hash-map
to hashmap
in mops.toml to be able to import like this
import Map "mo:hashmap/Map";
If you rename package in mops.toml
you need to run mops install
to install the package with new name.