Drop PGXN metadata, update README

Author: Sergey Shinderuk

META.json

@@ -20,12 +20,3 @@ top_builddir = ../..
 include $(top_builddir)/src/Makefile.global
 include $(top_srcdir)/contrib/contrib-global.mk
 endif
-
-# Prepare the package for PGXN submission
-package: dist .git
-	$(eval DISTVERSION := $(shell git tag -l | tail -n 1 | cut -d 'v' -f 2))
-	$(info Generating zip file for version $(DISTVERSION)...)
-	git archive --format zip --prefix=$(EXTENSION)-${DISTVERSION}/ --output dist/$(EXTENSION)-${DISTVERSION}.zip HEAD
-
-dist:
-	mkdir -p dist

Makefile

@@ -1,5 +1,4 @@
 [![Build Status](https://travis-ci.com/postgrespro/pg_wait_sampling.svg?branch=master)](https://travis-ci.com/postgrespro/pg_wait_sampling)
-[![PGXN version](https://badge.fury.io/pg/pg_wait_sampling.svg)](https://badge.fury.io/pg/pg_wait_sampling)
 [![GitHub license](https://img.shields.io/badge/license-PostgreSQL-blue.svg)](https://raw.githubusercontent.com/postgrespro/pg_wait_sampling/master/LICENSE)
 
 `pg_wait_sampling` – sampling based statistics of wait events
@@ -159,16 +158,6 @@ your bug reports.
 If you're lacking of some functionality in `pg_wait_sampling` and feeling power
 to implement it then you're welcome to make pull requests.
 
-Releases
---------
-
-New features are developed in feature-branches and then merged into [master](https://github.com/postgrespro/pg_wait_sampling/tree/master). To make a new release:
-
-1) Bump `PGXN` version in the `META.json`.
-2) Merge [master](https://github.com/postgrespro/pg_wait_sampling/tree/master) into [stable](https://github.com/postgrespro/pg_wait_sampling/tree/stable).
-3) Tag new release in the [stable](https://github.com/postgrespro/pg_wait_sampling/tree/stable) with `git tag -a v1.1.X`, where the last digit is used for indicating compatible shared library changes and bugfixes. Second digit is used to indicate extension schema change, i.e. when `ALTER EXTENSION pg_wait_sampling UPDATE;` is required.
-4) Merge [stable](https://github.com/postgrespro/pg_wait_sampling/tree/stable) into [debian](https://github.com/postgrespro/pg_wait_sampling/tree/debian). This separate branch is used to independently support `Debian` packaging and @anayrat with @df7cb have an access there. 
-
 Authors
 -------