[Fix] Update auth and order API versions

[ihor-chaban]

Updated auth (v4 to v5) and order (v7 to v8) API versions according to ahivert/tgtg-python@80859da
This fixes the broken reservations issue #531 and other potential issues related to orders.
Docker images I used for testing are available at gorus5/tgtg-scanner:latest-api and gorus5/tgtg-scanner:latest-alpine-api (multi-arch).
Reservations and orders worked fine, and I could create an order successfully.

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