update install agent run command

Author: SugatD

.github/workflows/ci.yml

@@ -94,7 +94,12 @@ jobs:
 
     - name: Install agent
       run: |
-        bundle exec rake 'litmus:install_agent[${{ matrix.collection.collection }}]'
+        if [[ "${{ matrix.collection.version }}" ]] ; then
+          export PUPPET_VERSION=${{ matrix.collection.version }}
+          bundle exec rake 'litmus:install_agent[${{ matrix.collection.collection }}]'
+        else
+          bundle exec rake 'litmus:install_agent[${{ matrix.collection }}]'
+        fi
 
     - name: Install module
       run: |