DX-2556: Switch to release drafter (#4302)

* DX-2556: Switch to release drafter, require Composer 2

* style fix

* composer 2

* style fix

* Don't require Composer 2 yet

* Fix travis

* code style

* fix robofile

* Fix test

.gitattributes

@@ -0,0 +1,5 @@
+tests export-ignore
+.editorconfig export-ignore
+.gitignore export-ignore
+.travis.yml export-ignore
+phpcs.xml.dist export-ignore

.github/release-drafter.yml

@@ -0,0 +1,28 @@
+name-template: '$RESOLVED_VERSION'
+tag-template: '$RESOLVED_VERSION'
+categories:
+  - title: '🚨 Major changes'
+    label: 'Breaking change'
+  - title: '🚀 Enhancements'
+    label: 'Enhancement'
+  - title: '🐛 Bug Fixes'
+    label: 'Bug'
+  - title: '🧰 Maintenance'
+    label: 'Chore'
+change-template: '- $TITLE @$AUTHOR (#$NUMBER)'
+change-title-escapes: '\<*_&' # You can add # and @ to disable mentions, and add ` to disable code blocks.
+version-resolver:
+  major:
+    labels:
+      - 'Breaking change'
+  minor:
+    labels:
+      - 'Enhancement'
+  patch:
+    labels:
+      - 'Bug'
+  default: patch
+template: |
+  ## What's new since $PREVIOUS_TAG
+
+  $CHANGES