Add arch to apt cache key (#34)

Fixes possible inconsistencies in caches between arm and x86_64 runners, which can cause errors like:

```
 
  The following packages have unmet dependencies:
   attr : Depends: libattr1 (= 1:2.5.2-1build1) but 1:2.5.2-1build1.1 is to be installed
   libdebuginfod1t64 : Depends: libelf1t64 (= 0.190-1.1build4) but 0.190-1.1build4.1 is to be installed
                       Depends: libdw1t64 (= 0.190-1.1build4) but 0.190-1.1build4.1 is to be installed
   uuid-dev : Depends: libuuid1 (= 2.39.3-9ubuntu6.1) but 2.39.3-9ubuntu6.2 is to be installed
  E: Unable to correct problems, you have held broken packages.

```
---------

Co-authored-by: ocaisa <alan.ocais@cecam.org>

Author: vvolkl

action.yml

@@ -340,13 +340,15 @@ runs:
           echo "codename=${DISTRIB_CODENAME}" >> $GITHUB_OUTPUT
           echo "description=${DISTRIB_DESCRIPTION}" >> $GITHUB_OUTPUT
           echo "id-release=${DISTRIB_ID}-${DISTRIB_DESCRIPTION}" >> $GITHUB_OUTPUT
+          echo "arch=$(uname -m)" >> $GITHUB_OUTPUT
         elif [ "$RUNNER_OS" == "macOS" ]; then
           echo "id-release=macOS-$(sw_vers -productVersion)" >> $GITHUB_OUTPUT
+          echo "arch=$(uname -m)" >> $GITHUB_OUTPUT
         fi
       shell: bash
     - uses: actions/cache@v4
       with:
-        key: cvmfs-apt-cache-${{ steps.lsb-release.outputs.id-release }}-${{ hashFiles('action.yml') }}
+        key: cvmfs-apt-cache-${{ steps.lsb-release.outputs.id-release }}-${{ steps.lsb-release.outputs.arch }}-${{ hashFiles('action.yml') }}
         path: |
           ${{ inputs.apt_cache }}
     - run: |