update release procedure

[skip ci]

extra/release-checklist.txt

@@ -19,13 +19,17 @@
 
 # Making the release
 
-- Copy relevant changelog part to downloads/$version/CHANGES.md.
-- Write announcement post.
-- Copy announcement post to downloads/$version/RELEASE.md.
-- Update downloads/versions.json
-- Push the generated binaries and installers to haxe.org, requires git-lfs
+- Regenerate API documentation (check --title and -D version values).
+- Make a GitHub release in https://github.com/HaxeFoundation/haxe/releases with
+  - the generated binaries and installers
+  - the API documentation
+- Update haxe.org
+  - Copy relevant changelog part to downloads/$version/CHANGES.md.
+  - Write announcement post in downloads/$version/RELEASE.md.
+  - Update downloads/versions.json.
+  - Push to staging, check https://staging.haxe.org/.
+  - Merge staging to master, check https://haxe.org/.
 
 # Announcing the release
 
-- Regenerate and upload API documentation (check --title and -D version values).
 - Post announcement post to haxelang.