Add automake to spec
    
    On Fedora Rawhide (f33) and Fedora ELN (rhel9)  libidn2 fails to build with the following error.

    

    + /usr/bin/make -O -j6 V=1 VERBOSE=1

    CDPATH="${ZSH_VERSION+.}:" && cd . && /bin/sh /builddir/build/BUILD/libidn2-2.3.0/build-aux/missing aclocal-1.16 -I m4 -I unistring/m4

    /builddir/build/BUILD/libidn2-2.3.0/build-aux/missing: line 81: aclocal-1.16: command not found

    

    This commit adds automake, which provides aclocal