Ignore the opensource.org bsd link, since it seems to give 403 for the check from github

Author: jasongrout

.github/workflows/validate.yml

@@ -87,7 +87,8 @@ jobs:
            --check-links-ignore "https://twitter.com/.*" \
            --check-links-ignore "https://jupytercon.com" \
            --check-links-ignore "https://www.netapp.com" \
-           --check-links-ignore "https://github.com/[^/]+/?$"   # 429 too many requests checking GitHub user profiles in about.html
+           --check-links-ignore "https://github.com/[^/]+/?$"   # 429 too many requests checking GitHub user profiles in about.html \
+           --check-links-ignore "https://opensource.org/licenses/BSD-3-Clause" # 403 forbidden from github
 
   lighthouse: