Add stackoverflow to links we skip

Author: choldgraf

.github/workflows/validate.yml

@@ -93,6 +93,7 @@ jobs:
            --check-links-ignore "https://sloan.org" \
            --check-links-ignore "https://www.bloomberg.com" \
            --check-links-ignore "https://www.oracle.com" \
+           --check-links-ignore "https://stackoverflow.com" \
            --check-links-ignore "https://opensource.org/licenses/BSD-3-Clause"
 
   lighthouse: