[EngSys] Install .NET 6.0 in workflows and pipelines (#354)

- Required now for workflow and pipeline to pass
- Long-term fix is to upgrade the version of .NET used by the tool

Author: mikeharder

.github/workflows/ci.yml

@@ -23,6 +23,10 @@ jobs:
         with:
           node-version: "20"
 
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: "6"
+
       - name: npm ci
         run: npm ci
 

eng/test-steps.yml

@@ -4,6 +4,9 @@ parameters:
     default: "drop"
 
 steps:
+  - task: UseDotNet@2
+    inputs:
+      version: 6.x
   - script: npm ci
     displayName: npm ci
   - script: npm run lint