Update RELEASING.md

Co-authored-by: Andreas Braun <[email protected]>

Author: GromNaN

RELEASING.md

@@ -85,7 +85,7 @@ After releasing a new major or minor version (e.g. 1.9.0), a maintenance branch
 1.9.1) would then be done within that branch and any development for the next
 major or minor release can continue in master.
 
-When work begins on a major new version, create a maintenance branch for the
+When work begins on a new major version, create a maintenance branch for the
 last minor version and update the `extra.branch-alias.dev-master` field
 in the master branch's `composer.json` file. For example, after branching v1.99,
 `composer.json` in the master branch may still read: