use explicit versions for flatfoot

This CL moves flatfoot libs to 1.0.0 if SL depends on them.
Also generated the api.txt for these libraries.

Bug: 65022193
Bug: 36069458
Test: checked generated zip file
Change-Id: I405d939e3d0b335a17bbed02eab1792ab6516612
diff --git a/lifecycle/extensions/build.gradle b/lifecycle/extensions/build.gradle
index b3530ea..71c90ef 100644
--- a/lifecycle/extensions/build.gradle
+++ b/lifecycle/extensions/build.gradle
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import android.support.LibraryVersions
 import android.support.SupportLibraryExtension
 
 apply plugin: android.support.FlatfootAndroidLibraryPlugin
@@ -55,6 +56,7 @@
 
 createAndroidCheckstyle(project)
 
+version = LibraryVersions.LIFECYCLES_EXT.toString()
 supportLibrary {
     name 'Android Lifecycle Extensions'
     publish true