Revert back to stable version master has different test versions

Author: aidangarske

.github/workflows/grpc.yml

@@ -75,14 +75,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - grpc_ref: 'v1.60.0'
-            tests: >-
-              bad_ssl_alpn_test bad_ssl_cert_test client_ssl_test
-              crl_ssl_transport_security_test server_ssl_test
-              ssl_transport_security_test ssl_transport_security_utils_test
-              test_core_security_ssl_credentials_test test_cpp_end2end_ssl_credentials_test
-              h2_ssl_cert_test h2_ssl_session_reuse_test
-          - grpc_ref: 'master'
+          - grpc_ref: v1.60.0 # TODO: Add master
             tests: >-
               bad_ssl_alpn_test bad_ssl_cert_test client_ssl_test
               crl_ssl_transport_security_test server_ssl_test