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.

Exempt-From-Owner-Approval: cherry-pick from aosp

Bug: 152655956
Test: m
Merged-In: Ifea5ed988fad2e0d29271e6e9cbf0e12100b37d9
Change-Id: Ifea5ed988fad2e0d29271e6e9cbf0e12100b37d9
(cherry picked from commit a395c8d9aa8e985d8c45f5dffa6518550a70d9a1)
diff --git a/libs/gui/Android.bp b/libs/gui/Android.bp
index 7f57f5d..7976ecb 100644
--- a/libs/gui/Android.bp
+++ b/libs/gui/Android.bp
@@ -27,6 +27,7 @@
         "android.hardware.graphics.bufferqueue@1.0",
         "android.hardware.graphics.bufferqueue@2.0",
     ],
+    min_sdk_version: "29",
 }
 
 cc_library_shared {