Bump actions/setup-node from 6.4.0 to 7.0.0 in the dotnet group

Bumps the dotnet group with 1 update: [actions/setup-node](https://github.com/actions/setup-node).


Updates `actions/setup-node` from 6.4.0 to 7.0.0
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@48b55a0...8207627)

---
updated-dependencies:
- dependency-name: actions/setup-node
  dependency-version: 7.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: dotnet
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/markdownlint.yml

@@ -16,7 +16,7 @@ jobs:
     steps:
     - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 #@v2
     - name: Use Node.js
-      uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e #@v1
+      uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 #@v1
       with:
         node-version: 12.x
     - name: Run Markdownlint