Update of dependencies

Maintenance of deps [ch5147] (#30)

* [ch5147] npm deps updated, fixed test, removed debug comments

* [ch5147] updated pre-commit script name

Retrieve Invoice endpoint

• [DP-468] Retrieve Invoice endpoint (#24)
• supports merged invoices for customers by default

v1.0.4

• support for Delete Invoice

List invoices for any customer endpoint

• adding possibility to list invoices across account

Deprecating Import & Enrichment

• Removing namespaces Import & Enrichment -> simpler library, converging to single API.
• Backwards compatible

v1.0.0: Merge pull request #18 from chartmogul/plan-tests

Adding mocked tests: plan (modify/destroy)