Bump actions/checkout from 2 to 4 (#162)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/Downstream.yml

@@ -27,14 +27,14 @@ jobs:
           - {user: BioJulia, repo: Automa.jl, group: TranscodingStreams}
           - {user: BioJulia, repo: FASTX.jl, group: TranscodingStreams}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v1
         with:
           version: ${{ matrix.julia-version }}
           arch: x64
       - uses: julia-actions/julia-buildpkg@latest
       - name: Clone Downstream
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           repository: ${{ matrix.package.user }}/${{ matrix.package.repo }}
           path: downstream