online audit: use GET instead of HEAD

I also removed the `-L` flag which is already present in
`HOMEBREW_CURL_ARGS`.

Closes Homebrew/homebrew#42352.

Signed-off-by: Baptiste Fontaine <batifon@yahoo.fr>

Library/Homebrew/cmd/audit.rb

@@ -434,7 +434,7 @@ class FormulaAuditor
 
     return unless @online
     begin
-      nostdout { curl "--connect-timeout", "15", "-IL", "-o", "/dev/null", homepage }
+      nostdout { curl "--connect-timeout", "15", "-o", "/dev/null", homepage }
     rescue ErrorDuringExecution
       problem "The homepage is not reachable (curl exit code #{$?.exitstatus})"
     end