Remove deprecated Google ping

[jcoyne]

See https://developers.google.com/search/blog/2023/06/sitemaps-lastmod-ping

Pinging with URL 'https://example.com/sitemap.xml.gz':
Ping failed for Google: #<OpenURI::HTTPError: 404 Sitemaps ping is deprecated. See https://developers.google.com/search/blog/2023/06/sitemaps-lastmod-ping.> (URL http://www.google.com/webmasters/tools/ping?sitemap=https%3A%2F%2Fexample.com%2Fsitemap.xml.gz)

[n-rodriguez]

ping @kjvarga

[dan-jensen]

Until someone contributes a PR to remove the Google ping from the defaults, it can be deleted from the defaults this way:

SitemapGenerator::Sitemap.search_engines.delete(:google)

Alternatively, because the Google ping is currently the only default, you could also do SitemapGenerator::Sitemap.search_engines = {}

[tbrammar]

Can't you just use rake sitemap:refresh:no_ping as per the documentation?

(obvs would be good to have it removed entirely)

[n-rodriguez]

Done in #444