Add cppref to the whitelist (#1138)

Author: tpadioleau

.github/workflows/website-checks.yaml

@@ -27,4 +27,9 @@ jobs:
           pipx install linkchecker~=10.6
       - name: Analysing the links of the website
         run: |
-          linkchecker --check-extern --ignore-url='.*_8hpp\.html' --ignore-url=https://www.doxygen.org/index.html --ignore-url=https://theses.fr/2022AIXM0412 index.html
+          linkchecker \
+            --check-extern \
+            --ignore-url='.*_8hpp\.html' \
+            --ignore-url=https://www.doxygen.org/index.html \
+            --ignore-url=https://en.cppreference.com/cpp/language/structured_binding \
+            --ignore-url=https://theses.fr/2022AIXM0412 index.html