docs: add release guide (#114)

Author: DominicGBauer

docs/Release.md

@@ -0,0 +1,8 @@
+# Powersync Kotlin SDK
+
+## How to make a release
+
+1. Update `LIBRARY_VERSION` in `gradle.properties` in the root.
+2. Add an entry to the `CHANGELOG.md`.
+3. Make a PR and merge it.
+4. Once the PR is merged and in the `main` branch then manually run the Github action `Deploy to Sonatype`. This will create a release to Maven Central and will also update the version of the `powersync-kotlin` SPM package used in the Swift SDK. If the release contains changes pertaining to the Swift SDK you will need to update the `powersync-kotlin` SPM package version in that repo and make a release there as well.