another CI doc deployment fix

Author: jacobwilliams

.github/workflows/CI.yml

@@ -162,7 +162,7 @@ jobs:
 
     - name: Rebuild documentation for tagged release
       env:
-        TAGNAME: ${{ steps.vars.outputs.tag }}
+        TAGNAME: ${{github.ref_name}}
       if: matrix.gcc_v == 7 && startsWith(github.ref, 'refs/tags/')
       run: |
         echo ${TAGNAME}