Build docs with Julia@v1.6

Author: findmyway

.github/workflows/ci.yml

@@ -146,7 +146,7 @@ jobs:
       - run: python -m pip install --user matplotlib
       - uses: julia-actions/setup-julia@v1
         with:
-          version: '1'
+          version: '1.6'
       - name: Build homepage
         run: |
           cd docs/homepage