remove arch in downgrade

.github/workflows/Downgrade.yml

@@ -27,9 +27,9 @@ jobs:
   downgrade_test:
     if: "!contains(github.event.head_commit.message, 'skip ci')"
     # We could also include the Julia version as in
-    # name: ${{ matrix.trixi_test }} - ${{ matrix.os }} - Julia ${{ matrix.version }} - ${{ matrix.arch }} - ${{ github.event_name }}
+    # name: ${{ matrix.trixi_test }} - ${{ matrix.os }} - Julia ${{ matrix.version }} - ${{ github.event_name }}
     # to be more specific. However, that requires us updating the required CI tests whenever we update Julia.
-    name: Downgrade ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}
+    name: Downgrade ${{ matrix.os }} - ${{ github.event_name }}
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
@@ -40,14 +40,11 @@ jobs:
           # - 'nightly'
         os:
           - ubuntu-latest
-        arch:
-          - x64
     steps:
       - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.version }}
-          arch: ${{ matrix.arch }}
       - run: julia -e 'using InteractiveUtils; versioninfo(verbose=true)'
       - uses: julia-actions/cache@v2
       - uses: julia-actions/julia-downgrade-compat@v1