audit: enforce https://*.sourceforge.io/ homepages

Ref: https://sourceforge.net/blog/introducing-https-for-project-websites/

Library/Homebrew/dev-cmd/audit.rb

@@ -584,6 +584,10 @@ class FormulaAuditor
       problem "Please use https:// for #{homepage}"
     end
 
+    if homepage =~ %r{^http://([^/]*)\.(sf|sourceforge)\.net(/|$)}
+      problem "#{homepage} should be `https://#{$1}.sourceforge.io/`"
+    end
+
     # There's an auto-redirect here, but this mistake is incredibly common too.
     # Only applies to the homepage and subdomains for now, not the FTP URLs.
     if homepage =~ %r{^http://((?:build|cloud|developer|download|extensions|git|glade|help|library|live|nagios|news|people|projects|rt|static|wiki|www)\.)?gnome\.org}

Library/Homebrew/test/audit_test.rb

@@ -431,6 +431,9 @@ class FormulaAuditorTests < Homebrew::TestCase
       "corge" => "http://savannah.nongnu.org/corge",
       "grault" => "http://grault.github.io/",
       "garply" => "http://www.gnome.org/garply",
+      "sf1" => "http://foo.sourceforge.net/",
+      "sf2" => "http://foo.sourceforge.net",
+      "sf3" => "http://foo.sf.net/",
       "waldo" => "http://www.gnu.org/waldo",
     }
 
@@ -455,6 +458,8 @@ class FormulaAuditorTests < Homebrew::TestCase
         end
       elsif homepage =~ %r{https:\/\/code\.google\.com}
         assert_match "#{homepage} should end with a slash", fa.problems.first
+      elsif homepage =~ /foo\.(sf|sourceforge)\.net/
+        assert_match "#{homepage} should be `https://foo.sourceforge.io/`", fa.problems.first
       else
         assert_match "Please use https:// for #{homepage}", fa.problems.first
       end