serde: make it available to any APEX

This seems necessary so that I can use it in the bytes crate.

Test: presubmit
Change-Id: Idbad0966173ffaaf773468906551d847790ec750
diff --git a/Android.bp b/Android.bp
index 425e605..bbdb479 100644
--- a/Android.bp
+++ b/Android.bp
@@ -56,9 +56,10 @@
     proc_macros: ["libserde_derive"],
     apex_available: [
         "//apex_available:platform",
-        "com.android.virt",
+        "//apex_available:anyapex",
     ],
     vendor_available: true,
+    min_sdk_version: "29",
 }
 
 rust_test {