chore(deps): update aszc/change-string-case-action action to v8

Author: renovate[bot]

.github/workflows/container-publish.yml

@@ -29,7 +29,7 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ github.token }}
       - id: string
-        uses: ASzc/change-string-case-action@v6
+        uses: ASzc/change-string-case-action@v8
         with:
           string: XCSoar