[CI] Publish draft release redux (#1493)

* Add publish-draft-release Github action
* Remove publish_draft_release.sh gitlab job

polkadot/scripts/github/generate_release_text.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require 'changelogerator'
+require 'git'
+require 'erb'
+require 'toml'
+
+version = ENV['GITHUB_REF']
+token = ENV['GITHUB_TOKEN']
+
+polkadot_path = ENV['GITHUB_WORKSPACE'] + '/polkadot/'
+pg = Git.open(polkadot_path)
+
+# Generate an ERB renderer based on the template .erb file
+renderer = ERB.new(
+  File.read(ENV['GITHUB_WORKSPACE'] + '/polkadot/scripts/github/polkadot_release.erb'),
+  trim_mode: '<>'
+)
+
+# get last polkadot version. Use handy Gem::Version for sorting by version
+last_version = pg
+              .tags
+              .map(&:name)
+              .grep(/^v\d+\.\d+\.\d+.*$/)
+              .sort_by { |v| Gem::Version.new(v.slice(1...)) }[-2]
+
+polkadot_cl = Changelog.new(
+  'paritytech/polkadot', version, last_version, token: token
+)
+
+# Get prev and cur substrate SHAs - parse the old and current Cargo.lock for
+# polkadot and extract the sha that way.
+prev_cargo = TOML::Parser.new(pg.show("#{last_version}:Cargo.lock")).parsed
+current_cargo = TOML::Parser.new(pg.show("#{version}:Cargo.lock")).parsed
+
+substrate_prev_sha = prev_cargo['package']
+                    .find { |p| p['name'] == 'sc-cli' }['source']
+                    .split('#').last
+
+substrate_cur_sha = current_cargo['package']
+                    .find { |p| p['name'] == 'sc-cli' }['source']
+                    .split('#').last
+
+substrate_cl = Changelog.new(
+  'paritytech/substrate', substrate_prev_sha, substrate_cur_sha,
+  token: token,
+  prefix: true
+)
+
+all_changes = polkadot_cl.changes + substrate_cl.changes
+
+# Set all the variables needed for a release
+
+misc_changes = Changelog.changes_with_label(all_changes, 'B1-releasenotes')
+client_changes = Changelog.changes_with_label(all_changes, 'B5-clientnoteworthy')
+runtime_changes = Changelog.changes_with_label(all_changes, 'B7-runtimenoteworthy')
+
+release_priority = Changelog.highest_priority_for_changes(all_changes)
+
+# Pulled from the previous Github step
+rustc_stable = ENV['RUSTC_STABLE']
+rustc_nightly = ENV['RUSTC_NIGHTLY']
+
+polkadot_runtime = File.open(polkadot_path + '/runtime/polkadot/src/lib.rs') do |f|
+  f.find { |l| l =~ /spec_version/ }.match(/[0-9]+/)[0]
+end
+kusama_runtime = File.open(polkadot_path + '/runtime/kusama/src/lib.rs') do |f|
+  f.find { |l| l =~ /spec_version/ }.match(/[0-9]+/)[0]
+end
+westend_runtime = File.open(polkadot_path + '/runtime/westend/src/lib.rs') do |f|
+  f.find { |l| l =~ /spec_version/ }.match(/[0-9]+/)[0]
+end
+
+puts renderer.result