Bump NetworkStack to system_30

NetworkStack can use system_30 now that system_30 exists.
This change moves the "current" API shims to api30, and adds an api31
shim.

Test: atest NetworkStackTests NetworkStackNextTests, manual (Wifi,
          telephony working)
Bug: 143586229
Change-Id: I37ca0e5a8a5c5620f5fed478648853b668e87f50
diff --git a/Android.bp b/Android.bp
index 81a96a8..efe8ff1 100644
--- a/Android.bp
+++ b/Android.bp
@@ -48,9 +48,10 @@
 
 java_defaults {
     name: "NetworkStackReleaseApiLevel",
-    sdk_version: "system_29",
+    // TODO: use system_30 once a prebuilt SDK is available for R
+    sdk_version: "system_current",
     min_sdk_version: "29",
-    target_sdk_version: "29",
+    target_sdk_version: "30",
 }
 
 // Filegroups for the API shims
@@ -60,6 +61,7 @@
         "apishim/common/**/*.java",
         "apishim/29/**/*.java",
         "apishim/30/**/*.java",
+        "apishim/31/**/*.java",
         ":networkstack-module-utils-srcs",
     ],
 }
@@ -71,6 +73,7 @@
     srcs: [
         "apishim/common/**/*.java",
         "apishim/29/**/*.java",
+        "apishim/30/**/*.java",
         ":networkstack-module-utils-srcs",
     ],
 }