tagging pg-wait-sampling 1.1.3-2

Release v1.1.3

* Fixed issue with collector detach from the shm_mq in the case of
ERROR/FATAL.
[PR#31](postgrespro#31).

Release 1.1.2

* Add PostgreSQL 13 support (postgrespro#24, thanks to @rjuju).
* Fixed wrong milliseconds calculation in the millisecs_diff() (postgrespro#25,
thanks to @kasaharatt).

- Add Postgres 12 support

- Various bugfixes

Add META file for pgxn