Fix versions in Branches

Author: k163377

README.md

@@ -256,8 +256,8 @@ See the [main Jackson contribution guidelines](https://github.com/FasterXML/jack
 
 If you are going to write code, choose the appropriate base branch:
 
-- `2.17` for bugfixes against the current stable version
-- `2.18` for additive functionality & features or [minor](https://semver.org), backwards compatible changes to existing behavior to be included in the next minor version release
+- `2.18` for bugfixes against the current stable version
+- `2.19` for additive functionality & features or [minor](https://semver.org), backwards compatible changes to existing behavior to be included in the next minor version release
 - `master` for significant changes to existing behavior, which will be part of Jackson 3.0
 
 ### Failing tests