#138 Installed mono in workflow (#139)

> 1. What triggered this change? (PBI link, Email Subject, conversation
+ reason, etc)

Resolved #138 

> 2. What was changed?

Installed Mono in the release workflow 

> 3. Did you do pair or mob programming?

@lukecookssw 
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Author: sam-s-maher

.github/workflows/package.yml

@@ -19,6 +19,9 @@ jobs:
         with:
           nuget-version: '6.x'
 
+      - name: Install Mono
+        run: sudo apt-get update && sudo apt-get install -y mono-complete
+
       - name: Create the package
         run: nuget pack VerticalSliceArchitecture.nuspec -NoDefaultExcludes