Fix open-uri call (#319)

Without this fix downloading will fail like:

Host OS...                                                                 linux
Attempting to download Arduino 0.13.0 package with open-uribundler: failed to load command: arduino_ci.rb (/.../vendor/bundle/ruby/3.0.0/bin/arduino_ci.rb)
/.../arduino_ci/lib/arduino_ci/arduino_downloader.rb:111:in `initialize': No such file or directory @ rb_sysopen - https://github.com/arduino/arduino-cli/releases/download/0.13.0/arduino-cli_0.13.0_Linux_64bit.tar.gz (Errno::ENOENT)

and when running through trace the log gives:

access("/usr/bin/tar", X_OK)            = 0
newfstatat(AT_FDCWD, "/usr/bin/tar", {st_mode=S_IFREG|0755, st_size=527464, ...}, 0) = 0
newfstatat(AT_FDCWD, "arduino-cli_0.13.0_Linux_64bit.tar.gz", 0x7fff95f8caa0, 0) = -1 ENOENT (No such file or directory)
write(1, "Attempting to download Arduino 0.13.0 package with open-uri", 59) = 59
openat(AT_FDCWD, "https://github.com/arduino/arduino-cli/releases/download/0.13.0/arduino-cli_0.13.0_Linux_64bit.tar.gz", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
ioctl(2, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(1, TCGETS, {B38400 opost isig icanon echo ...}) = 0

so obviously the bare open call is mapped to a filesystem open call.
The gem 'open-uri' is referenced earlier in the file and is obviously
the intended target. https://github.com/ruby/open-uri documents the API
to be URI.open, and substituting with that made downloading work.

Author: hlovdal

Diff for: lib/arduino_ci/arduino_downloader.rb

@@ -108,7 +108,7 @@ def download
         dots = needed_dots
       end
 
-      open(package_url, ssl_verify_mode: 0, progress_proc: dot_printer) do |url|
+      URI.open(package_url, ssl_verify_mode: 0, progress_proc: dot_printer) do |url|
         File.open(package_file, 'wb') { |file| file.write(url.read) }
       end
     rescue Net::OpenTimeout, Net::ReadTimeout, OpenURI::HTTPError, URI::InvalidURIError => e