Merge pull request #546 from SciML/dependabot/github_actions/actions/checkout-3

Bump actions/checkout from 2 to 3

Author: ChrisRackauckas

.github/workflows/CompatHelper.yml

@@ -10,7 +10,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Pkg.add("CompatHelper")
         run: julia -e 'using Pkg; Pkg.add("CompatHelper")'
       - name: CompatHelper.main()