Update CITATION.cff for v0.8.0

Author: lkdvos

CITATION.cff

@@ -14,8 +14,8 @@ authors:
     given-names: "Lukas"
     orcid: "https://orcid.org/0000-0002-0256-4200"
 title: "PEPSKit"
-version: 0.7.0
+version: 0.8.0
 identifiers:
   - type: doi
     value: 10.5281/zenodo.13938737
-date-released: 2025-08-06
+date-released: 2026-05-08