formatter: use v2 bcs v3 is not released yet

Author: Maximilian-Stefan-Ernst

.github/workflows/FormatCheck.yml

@@ -7,7 +7,7 @@ jobs:
   code-style:
     runs-on: ubuntu-latest
     steps:
-      - uses: julia-actions/julia-format@v3
+      - uses: julia-actions/julia-format@v2
         with:
           version: '1'
           suggestion-label: 'format-suggest'