Set min_sdk_version to be part of mainline modules

Modules contributing mainline modules (APK/APEX) should set
min_sdk_version as well as apex_available.

For now setting min_sdk_version doesn't change build outputs.
But build-time checks will be added soon.

Bug: 152655956
Test: m
Change-Id: I58ce4d2f486dfce33b6335d45ca8070dfb4edd46
diff --git a/Android.bp b/Android.bp
index 6cdd4da..eb03cd8 100644
--- a/Android.bp
+++ b/Android.bp
@@ -57,10 +57,11 @@
         },
     },
     apex_available: [
-       "//apex_available:platform",
-       "com.android.adbd",
-       "com.android.media.swcodec",
+        "//apex_available:platform",
+        "com.android.adbd",
+        "com.android.media.swcodec",
     ],
+    min_sdk_version: "29",
 }
 
 cc_binary {