Fix PR title

Signed-off-by: Yuri Shkuro <github@ysh.us>

RELEASE.md

@@ -1,6 +1,6 @@
 # Jaeger Backend Release Process
 
-1. Create a PR "Preparing release X.Y.Z" against master or maintenance branch ([example](https://github.com/jaegertracing/jaeger/pull/543/files)) by updating CHANGELOG.md to include:
+1. Create a PR "Prepare release X.Y.Z" against master or maintenance branch ([example](https://github.com/jaegertracing/jaeger/pull/543/files)) by updating CHANGELOG.md to include:
     * A new section with the header `<X.Y.Z> (YYYY-MM-DD)`
     * A curated list of notable changes and links to PRs. Do not simply dump git log, select the changes that affect the users. To obtain the list of all changes run `make changelog` or use `scripts/release-notes.py`.
     * The section can be split into sub-section if necessary, e.g. UI Changes, Backend Changes, Bug Fixes, etc.