ci: update the nuget/setup-nuget Action in the custom Actions

Git for Windows' automation has a couple of custom, composite Actions.
Naturally, Dependabot has no idea about those and could not help us
avoid those `Node.js 16 Actions are deprecated` warnings there, so let's
do it manually. This trick was performed via:

  f() {
    sed -i 's|\('"$1"'@v\)[0-9]*|\1'"$2"'|g' $(git grep -l "$1"@v)
  }
  f nuget/setup-nuget 2

Signed-off-by: Johannes Schindelin <[email protected]>

.github/actions/nuget-packages/action.yml

@@ -66,7 +66,7 @@ runs:
             ${{ inputs.git_artifacts_x86_64_workflow_run_id }},
             'nuget-x86_64'
           )
-    - uses: nuget/setup-nuget@v1
+    - uses: nuget/setup-nuget@v2
     - name: Upload NuGet packages
       shell: bash
       run: |