Update README.md

Author: pjfanning

README.md

@@ -28,7 +28,7 @@ Scala Case Classes, `Sequence`s, `Map`s, `Tuple`s, `Option`s, and Enumerations.
 # Version Support
 
 Jackson-module-scala follows the same release strategy of [jackson-databind](https://github.com/FasterXML/jackson-databind).
-Master branch is used for Jackson 3 development.
+3.x branch is used for Jackson 3 development.
 
 Scala 2.11, 2.12 and 2.13 are supported. Scala 2.10 support was dropped in v2.12.0 (but there is a special v2.12.7 release). Java 8 is
 the minimum supported version now.
@@ -128,7 +128,7 @@ ObjectMapper mapper = JsonMapper.builder().addModule(DefaultScalaModule$.MODULE$
 
 # Building
 
-The master branch often depends on SNAPSHOT versions of the core Jackson projects,
+The branches often depends on SNAPSHOT versions of the core Jackson projects,
 which are published to the Sonatype OSS Repository. To make these dependencies available,
 create a file called `sonatype.sbt` in the same directory as `build.sbt` with the following
 content. The project `.gitignore` file intentionally prevents this file from being checked in.