InProcessTethering: set min_sdk_version

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

InProcessTethering is a part of com.android.tethering.inprocess,
therefore min_sdk_version is set.

Exempt-From-Owner-Approval: CP from AOSP

Bug: 145796956
Bug: 150999716
Test: m
Merged-In: I655211e0b9aa4bd7cb3718b6f567f0aa1a0176a5
Change-Id: I655211e0b9aa4bd7cb3718b6f567f0aa1a0176a5
(cherry picked from commit ace605ef568fecfe148d2785f4681c9c858487aa)
diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 735dd17..1ee017b 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -115,6 +115,7 @@
     // InProcessTethering is a replacement for Tethering
     overrides: ["Tethering"],
     apex_available: ["com.android.tethering"],
+    min_sdk_version: "current",
 }
 
 // Updatable tethering packaged as an application