audit: online - limit download time based on HTTPS determination

Previously, the http_content_headers_and_checksum method always
downloaded the entire url, including headers. These downloads
periodically hang, outputting false positives or wreaking havoc on
the CI. Therefore, use curl's --max-time arg to prevent this by
setting a hard limit of 600 seconds when the entire file is going
to be used to detect whether the url can be changed to use the HTTPS
protocol instead of HTTP. Otherwise, if the url already is HTTPS, limit
the download time to 25 seconds since only the headers, not contents, matter.

Library/Homebrew/dev-cmd/audit.rb

@@ -177,8 +177,9 @@ class FormulaAuditor
 
     details = nil
     user_agent = nil
+    hash_needed = url.start_with?("http:")
     user_agents.each do |ua|
-      details = http_content_headers_and_checksum(url, user_agent: ua)
+      details = http_content_headers_and_checksum(url, hash_needed: hash_needed, user_agent: ua)
       user_agent = ua
       break if details[:status].to_s.start_with?("2")
     end
@@ -188,11 +189,11 @@ class FormulaAuditor
       return "The URL #{url} is not reachable (HTTP status code #{details[:status]})"
     end
 
-    return unless url.start_with? "http:"
+    return unless hash_needed
 
     secure_url = url.sub "http", "https"
     secure_details =
-      http_content_headers_and_checksum(secure_url, user_agent: user_agent)
+      http_content_headers_and_checksum(secure_url, hash_needed: true, user_agent: user_agent)
 
     if !details[:status].to_s.start_with?("2") ||
        !secure_details[:status].to_s.start_with?("2")
@@ -210,9 +211,10 @@ class FormulaAuditor
     "The URL #{url} could use HTTPS rather than HTTP"
   end
 
-  def self.http_content_headers_and_checksum(url, user_agent: :default)
+  def self.http_content_headers_and_checksum(url, hash_needed: false, user_agent: :default)
+    max_time = hash_needed ? "600" : "25"
     args = curl_args(
-      extra_args: ["--connect-timeout", "15", "--include", url],
+      extra_args: ["--connect-timeout", "15", "--include", "--max-time", max_time, url],
       show_output: true,
       user_agent: user_agent,
     )
@@ -224,11 +226,13 @@ class FormulaAuditor
       status_code = headers[%r{HTTP\/.* (\d+)}, 1]
     end
 
+    output_hash = Digest::SHA256.digest(output) if hash_needed
+
     {
       status: status_code,
       etag: headers[%r{ETag: ([wW]\/)?"(([^"]|\\")*)"}, 2],
       content_length: headers[/Content-Length: (\d+)/, 1],
-      file_hash: Digest::SHA256.digest(output),
+      file_hash: output_hash,
     }
   end