Skip make update-unicode for BASERUBY CI
Unfortunately it often fails depending on the status of www.unicode.org.
https://github.com/mame/ruby/runs/2761346164?check_suite_focus=true
./tool/downloader.rb:248:in `rescue in download': failed to download 12.1.0/ucd/UnicodeData.txt (RuntimeError) OpenSSL::SSL::SSLError: SSL_connect returned=1 errno=0 state=error: certificate verify failed: https://www.unicode.org/Public/12.1.0/ucd/UnicodeData.txt
Skip make update-unicode for BASERUBY CI
Unfortunately it often fails depending on the status of www.unicode.org.
https://github.com/mame/ruby/runs/2761346164?check_suite_focus=true