Add release management docs (#509)

add release management docs

Author: hrach

contributing.md

@@ -40,3 +40,25 @@ To generate new screenshots, run the **gradle task**:
 To verify the implementation matches the recorded screenshots, run
 
 `./gradlew :ui:verifyPaparazziDebug`
+
+## Release management
+
+### Next release's version
+
+The next release version is auto-resolved by the merged pull requests. After each push to main branch, there is a workflow that considers merged PRs since the last release and bumps/changes the next version if needed.
+
+PRs can be labeled with `semver:major`, `semver:minor` or `semver:patch` labels. The workflow considers the "biggest" needed bump. If there are no labeled PRs, it uses a minor version bump by default.
+
+The workflow also updates the next "drafted" release with the proper version title and description (list of merged PRs). Those PRs are grouped by labels like `feature`, `bug` or `chore`.
+
+### Releasing the next version
+
+1. Edit the drafted release at https://github.com/kiwicom/orbit-compose/releases.
+2. Make edits in the description — if needed.
+3. Press "Publish release" button.
+
+This action will:
+- publish the GitHub release,
+- tag the latest commit with the appropriate git tag,
+- build the commit and publish the libraries to Maven's staging & auto-promote it to the public,
+- build the catalog app and upload it to the GitHub release and publish it automatically on Google Play.