Added pre suffix to pack command

Author: synercoder

.github/workflows/dotnet-core.yml

@@ -42,7 +42,7 @@ jobs:
         run: dotnet test -c Release
       - name: Pack
         if: matrix.os == 'ubuntu-latest'
-        run: dotnet pack -v normal -c Release --no-restore --include-symbols --include-source -p:SymbolPackageFormat=snupkg -p:PackageVersion=$GITHUB_RUN_ID src/$PROJECT_NAME/$PROJECT_NAME.*proj
+        run: dotnet pack -v normal -c Release --no-restore --include-symbols --include-source -p:SymbolPackageFormat=snupkg -p:PackageVersion=$GITHUB_RUN_ID-pre src/$PROJECT_NAME/$PROJECT_NAME.*proj
       - name: Upload Artifact
         if: matrix.os == 'ubuntu-latest'
         uses: actions/upload-artifact@v2