package/libsoup: bump to version 2.72.0

package/libsoup: bump to version 2.72.0

Among other fixes, switching to the current stable version plugs a few
memory leaks; solves many WebSocket bugs; makes NTLM authentication work;
allows building gobject-introspection data when cross-building (to be
enabled in a separate patch); fixes message cancellation; adds support
for HTTP 308 permanent redirects, same-site cookies, secure cookies,
HSTS, and Brotli compression.

This also removes the unneeded LIBSOUP_CONF_ENV which defined an
autoconf variable, and updates the Meson build configuration options
to follow the changes done by upstream.

Signed-off-by: Adrian Perez de Castro <aperez@igalia.com>
[yann.morin.1998@free.fr:
  - reorder options and move them one per line
  - while at it, do the same for dependencies
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>