chore: test "dotnet pack" in CI (#851)

* chore: test "dotnet pack" in CI

Author: ajewellamz

.github/workflows/ci_test_net.yml

@@ -104,3 +104,12 @@ jobs:
           else
             make test_net FRAMEWORK=net6.0
           fi
+      
+      - name: Test Build and Pack ${{ matrix.library}}
+        shell: bash
+        if: matrix.os != 'windows-latest'
+        working-directory: ./${{ matrix.library }}
+        run: |
+          dotnet build runtimes/net /p:Configuration=Release -nowarn:CS0162,CS0168
+          dotnet pack runtimes/net/DynamoDbEncryption.csproj --no-build /p:Configuration=Release --output build
+