mod_md v2.4.9

• MDExternalAccountBinding can be configured with a file that contains the
  'kid' and 'hmac' values in JSON format. Since httpd config files are often
  readable to non-admins, this allows to keep those values in a more protected
  file.
• OpenSSL 3.0 compatibility: fixed generation of Elliptic Curve private
  keys to work with openssl 3.0.0.
• Docker testing arrived. Run make docker-test in your mod_md directory
  to build and test the current sources in a Debian sid image.
• The directive 'MDCertificateAuthority' now checks if its parameter is a http/https
  url or one of a set of known names. Those are 'LetsEncrypt', 'LetsEncrypt-Test',
  'Buypass' and 'Buypass-Test' for now and they are not case-sensitive.
  The default of LetsEncrypt is unchanged.
• Fixed a bug that reset the error counter of a certificate renewal and
  prevented the increasing delays in further attempts. Test case 741 added
  to verify the correct behaviour.