message: Fix action so that it captures 2020 in copyrights
diff: @@ -21,9 +21,9 @@ jobs:
  - name: copyright check
  run: |
  cd MFEM
  - if git grep -l "\-2021" > matches.txt
  + if git grep -l "\-2020" > matches.txt
  then
  - echo "Some files with outdated copyrights where found."
  + echo "Some files with outdated copyrights were found."
  echo "Please update to 2021. Here is the list:"
  cat matches.txt
  exit 1
  