raise dependency on libcouchbase 3.2.2

drop patch merged upstream
raise dependency on libcouchbase 3.2

raise dependency on libcouchbase 3.1

drop patches merged upstream
add patch for PHP 7.2 from
  https://github.com/couchbase/php-couchbase/pull/32

rename to php-pecl-couchbase3
raise dependency on PHP 7.1
raise dependency on libcouchbase 3.0
drop dependency on igbinary extension