fix: properly use a step to get the version number

.github/workflows/reusable-build-image.yml

@@ -38,7 +38,6 @@ env:
   IMAGE_REGISTRY: "ghcr.io/${{ github.repository_owner }}"
   DEFAULT_TAG: "lts"
   CENTOS_VERSION: ${{ inputs.centos-version }}
-  CENTOS_VERSION_NUMBER: ${{ inputs.centos-version | tr -d -c 0-9 }}
   PLATFORMS: ${{ inputs.platforms }}
 
 jobs:
@@ -264,6 +263,12 @@ jobs:
           # https://linux.die.net/man/1/date
           echo "date=$(date -u +%Y\-%m\-%d\T%H\:%M\:%S\Z)" >> $GITHUB_OUTPUT
 
+      - name: Extract numbers from input
+        id: extract-numbers
+        run: |
+          numbers_only=$(echo "${{ env.CENTOS_VERSION }}" | tr -cd '0-9')
+          echo "CENTOS_VERSION_NUMBER=$numbers_only" >> $GITHUB_ENV
+
       - name: Image Metadata
         uses: docker/metadata-action@369eb591f429131d6889c46b94e711f089e6ca96 # v5
         id: metadata