install .net sdks for smoke tests (#276)

* install .net sdks for smoke tests

* collapsing steps into a single one

Author: srprash

.github/workflows/continuous-monitoring.yml

@@ -27,6 +27,13 @@ jobs:
                aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
                aws-region: us-east-1
 
+          - name: Setup dotnet
+            uses: actions/setup-dotnet@v1
+            with:
+              dotnet-version: |
+                3.1.x
+                6.0.x
+
           - name: Install dependencies
             run: dotnet restore sdk/test/SmokeTests/AWSXRayRecorder.SmokeTests.csproj