Update autoconf-archive to version 2021.02.19 / rev 26 via SR 874166
    
    https://build.opensuse.org/request/show/874166
    by user dirkmueller + dimstar_suse
    - update to 2021.02.19:
      * The macros AX_CHECK_PCRE2 and AX_PROG_ROBOT have been added. Many other
        macros have received updates.
    
    - Drop info Requires(pre|post) and usage of install_info and
      install_info_delete in the pre/post scriptlets: info files are
      handled by file triggers.