[Release] Updated version to 1.8.0 for the 1.8.0 stable release.

build.gradle

@@ -55,7 +55,7 @@ ext {
     ? project.property('mavenRepoUrl') : '/tmp/myRepo/')
 
   // Current version of the library (could be in-development/unreleased).
-  mdcLibraryVersion = '1.8.0-rc01'
+  mdcLibraryVersion = '1.8.0'
   mdcLibraryPackage = "com.google.android.material"
   mdcLibraryDir = "com/google/android/material"
 }