Spoof user agent for noaa.gov links

Author: brian-rose

_config.yml

@@ -29,6 +29,9 @@ sphinx:
   config:
     linkcheck_ignore: ["https://doi.org/*", "https://zenodo.org/badge/*"] # don't run link checker on DOI links since they are immutable
     nb_execution_raise_on_error: true # raise exception in build if there are notebook errors (this flag is ignored if building on binder)
+    linkcheck_request_headers:
+       "https://*.noaa.gov/":
+         User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:24.0) Gecko/20100101 Firefox/24.0
     html_favicon: notebooks/images/icons/favicon.ico
     html_last_updated_fmt: "%-d %B %Y"
     html_theme: sphinx_pythia_theme