Bump gitversion.tool from 6.7.0 to 6.8.0

---
updated-dependencies:
- dependency-name: gitversion.tool
  dependency-version: 6.8.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.config/dotnet-tools.json

@@ -17,7 +17,7 @@
       "rollForward": false
     },
     "gitversion.tool": {
-      "version": "6.7.0",
+      "version": "6.8.0",
       "commands": [
         "dotnet-gitversion"
       ],