TaxonomyService::getVocabulary does not respect context argument

[DrillSergeant]

Steps to reproduce:

1. create a vocabulary (in my example called 'applications') and some taxonomies inside
2. switch to another dimension and change the title of one taxonomy to something different
3. access the taxonomie-nodes via fusion:
   ${q(Taxonomy.vocabulary('applications', site.context)).children()}

Expected behaviour:
You get the taxonomy-nodes of the current site-context (in the correct dimension)

Actual behaviour:
You get the taxonomy-nodes of the default site-context (in the default dimension)

Possible solution
I am quite sure the probem is that TaxonomyService::getVocabulary does not hand over the context argument when fetching the root-node. I will create a pull request to fix this.

Workaround
As a workaround in my fusion-code, I get the taxonomies meanwhile this way:
items = ${q(Taxonomy.root(site.context)).children('applications').children()}