Fix tests according to latest spec

[TG1999]

Reference:

• Expected output in testcases do not follow spec encoding purl-spec#644

[mjherzog]

Closing - see - package-url/purl-spec#644

[mjherzog]

I should not have closed this Issue - I confused it with a similar purl-spec issue

[kdeldycke]

There is a big discrepancy in the repository right now. The spec submodule is currently pinned to c398646, which is not on any branch or tag of purl-spec. It was done in #206 .

It sits on an unmerged side branch, that has 11 commits not part of the main branch at all: package-url/purl-spec@9b27957...c398646

In the mean time, there is a v1.0.0 tag that is 204 commits ahead.

I use the current state of spec as the source of truth in #188 , but I think we need to pin the spec submodule to v1.0.0 and fix everything. Would you be interested in such a PR?