chore: use new major versions of arcus packages

[stijnmoreels]

Use the new major release versions of the Arcus packages Observability and Security, both with the .NET 8 support.

Relates to arcus-azure/arcus#311

[netlify]

✅ Deploy Preview for arcus-webapi canceled.

Name	Link
🔨 Latest commit	1262750
🔍 Latest deploy log	https://app.netlify.com/sites/arcus-webapi/deploys/65d33e249a9f1a0007ca5dee

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (b6ec764) 82.93% compared to head (1262750) 82.92%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #460      +/-   ##
==========================================
- Coverage   82.93%   82.92%   -0.02%     
==========================================
  Files          49       49              
  Lines        1664     1663       -1     
  Branches      152      152              
==========================================
- Hits         1380     1379       -1     
  Misses        220      220              
  Partials       64       64              

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