Bump gittools/actions from 0.9.7 to 0.9.15

Bumps [gittools/actions](https://github.com/gittools/actions) from 0.9.7 to 0.9.15.
- [Release notes](https://github.com/gittools/actions/releases)
- [Commits](GitTools/actions@v0.9.7...v0.9.15)

---
updated-dependencies:
- dependency-name: gittools/actions
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/merge-main.yml

@@ -203,13 +203,13 @@ jobs:
           fetch-depth: 0                # fetch the whole repo history
 
       - name: Setup GitVersion
-        uses: gittools/actions/gitversion/[email protected].7
+        uses: gittools/actions/gitversion/[email protected].15
         with:
           versionSpec: '5.x'
 
       - name: Determine SemVersion
         id:   gitversion
-        uses: gittools/actions/gitversion/[email protected].7
+        uses: gittools/actions/gitversion/[email protected].15
         with:
           useConfigFile: true
           configFilePath: GitVersion.yaml