Fix lifecycle-runtime for compileSdkVersion 28 + minification

bug: 142778206
Test: manually ran a testcase from b/142778206
Change-Id: I81b47999effbd1e099a8876b9133db4f8a0d899b
diff --git a/lifecycle/lifecycle-process/proguard-rules.pro b/lifecycle/lifecycle-process/proguard-rules.pro
new file mode 100644
index 0000000..ff27e9d
--- /dev/null
+++ b/lifecycle/lifecycle-process/proguard-rules.pro
@@ -0,0 +1,2 @@
+# this rule is need to work properly when app is compiled with api 28, see b/142778206
+-keepclassmembers class * extends androidx.lifecycle.EmptyActivityLifecycleCallbacks { *; }
\ No newline at end of file