Upgrade libsrtp to version 2.0

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index f52958759253920952ed119a8646966dd02f9b7c..53f1145b15255c4c6b65f8b9060895fbe4e252e9 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -789,20 +789,7 @@ group("gn_only") {
       "//third_party/leveldatabase:leveldb_version_edit_test",
       "//third_party/leveldatabase:leveldb_write_batch_test",
       "//third_party/libjpeg_turbo:simd",
-      "//third_party/libsrtp:rdbx_driver",
-      "//third_party/libsrtp:replay_driver",
-      "//third_party/libsrtp:roc_driver",
-      "//third_party/libsrtp:rtpw",
-      "//third_party/libsrtp:srtp_driver",
-      "//third_party/libsrtp:srtp_driver",
-      "//third_party/libsrtp:srtp_test_aes_calc",
-      "//third_party/libsrtp:srtp_test_cipher_driver",
-      "//third_party/libsrtp:srtp_test_datatypes_driver",
-      "//third_party/libsrtp:srtp_test_env",
-      "//third_party/libsrtp:srtp_test_kernel_driver",
-      "//third_party/libsrtp:srtp_test_rand_gen",
-      "//third_party/libsrtp:srtp_test_sha1_driver",
-      "//third_party/libsrtp:srtp_test_stat_driver",
+      "//third_party/libsrtp:srtp_tests",
       "//third_party/opus:opus_compare",
       "//third_party/opus:opus_demo",
       "//third_party/opus:test_opus_api",