Build r8 without dependencies without dependencies

Pass the jar with dependencies as library not program when building
r8lib with external dependencies (r8lib-exclude-deps.jar).

Change-Id: I9bbf495db13891d0eba3c61b724202a082fed391

build.gradle

diff --git a/build.gradle b/build.gradle
index 23d3e0c..cdf2b9c 100644
--- a/build.gradle
+++ b/build.gradle
@@ -925,6 +925,7 @@
             ["src/main/keep.txt", "src/main/keep-applymapping.txt", genRulesTask.outputs.files[0]],
             R8NoManifestNoDeps,
             r8LibExludeDepsPath,
+            "--release",
             repackageDepsNoRelocate.outputs.files
     ).dependsOn(repackageDepsNoRelocate, genRulesTask)
     outputs.file r8LibExludeDepsPath