Update version to 6.1-alpha.

build.gradle

@@ -44,7 +44,7 @@ subprojects {
   apply plugin: 'org.junit.platform.gradle.plugin'
   junitPlatform { filters { engines { 'junit-jupiter' } } }
   group = 'org.ow2.asm'
-  version = '6.1-beta'
+  version = '6.1-alpha'
   sourceCompatibility = '1.6'
   targetCompatibility = '1.6'
   ext.provides = []  // The provided java packages, e.g. ['org.objectweb.asm']