update grpc library to 1.20.0

This is part two of the three step dance. The 1.20.0 libraries have been committed to GoB https://github.com/bazelbuild/bazel/commit/0dbbb4c07e17df4112ea89825da9dc3e9dbabbac

The third step is to remove the old libraries from third_party (they are unused as of this CL).

RELNOTES: None
PiperOrigin-RevId: 243561302
diff --git a/scripts/bootstrap/compile.sh b/scripts/bootstrap/compile.sh
index bc97e9e..db7be55 100755
--- a/scripts/bootstrap/compile.sh
+++ b/scripts/bootstrap/compile.sh
@@ -18,7 +18,7 @@
 
 PROTO_FILES=$(ls src/main/protobuf/*.proto src/main/java/com/google/devtools/build/lib/buildeventstream/proto/*.proto)
 LIBRARY_JARS=$(find third_party -name '*.jar' | grep -Fv JavaBuilder | grep -Fv third_party/guava | grep -Fv third_party/guava | grep -ve 'third_party/grpc/grpc.*jar' | tr "\n" " ")
-GRPC_JAVA_VERSION=1.10.0
+GRPC_JAVA_VERSION=1.20.0
 GRPC_LIBRARY_JARS=$(find third_party/grpc -name '*.jar' | grep -e ".*${GRPC_JAVA_VERSION}.*jar" | tr "\n" " ")
 GUAVA_VERSION=25.1
 GUAVA_JARS=$(find third_party/guava -name '*.jar' | grep -e ".*${GUAVA_VERSION}.*jar" | tr "\n" " ")