[Release] Marked library version to 1.13.0-alpha03.

PiperOrigin-RevId: 640961830

build.gradle

@@ -58,7 +58,7 @@ ext {
  ? project.property('mavenRepoUrl') : '/tmp/myRepo/')
 
  // Current version of the library (could be in-development/unreleased).
- mdcLibraryVersion = '1.13.0-alpha02'
+ mdcLibraryVersion = '1.13.0-alpha03'
  mdcLibraryPackage = "com.google.android.material"
  mdcLibraryDir = "com/google/android/material"
 }