SWPROT-8953: ci: Pull annotated tag

After further investigations, the reason that script failed to use
the git describe in github it because of a bug in related github action

Relate-to: actions/checkout#2081
Origin: SiliconLabsSoftware#42
Relate-to: SiliconLabsSoftware#35
Signed-off-by: Philippe Coval <philippe.coval@silabs.com>

.github/workflows/build-rootfs.yml

@@ -16,9 +16,12 @@ jobs:
           - arm64
           # - armhf # TODO Enable when supported
     steps:
-      - uses: actions/checkout@v4.1.1
+      - uses: actions/checkout@v4.2.2
         with:
           fetch-depth: 0
+          # Relate-to: https://github.com/actions/checkout/pull/2081#2025
+          ref: ${{ github.ref }}
+
       - id: describe
         name: Describe HEAD
         run: >-