Allow S3 buckets to have dots

Closes Homebrew/homebrew#49729.

Signed-off-by: Tim D. Smith <git@tim-smith.us>

Library/Homebrew/download_strategy.rb

@@ -451,7 +451,7 @@ class S3DownloadStrategy < CurlDownloadStrategy
       raise
     end
 
-    if @url !~ %r{^https?://+([^.]+).s3.amazonaws.com/+(.+)$}
+    if @url !~ %r{^https?://+([^.].+).s3.amazonaws.com/+(.+)$}
       raise "Bad S3 URL: " + @url
     end
     bucket = $1