Specify min_sdk_version so it can be used with APEX. am: c381ccc21c am: 1e505f1880

Original change: https://android-review.googlesource.com/c/platform/external/opencensus-java/+/2360920

Change-Id: I8ff31a9f1f6a6b662eea2c9a5ebe57245c13c173
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>