[interop] Add v1.60.0 release of grpc-go to interop matrix (#35282)

Closes #35282

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/35282 from easwars:go_release a2c695cb1e
PiperOrigin-RevId: 591284158

tools/interop_matrix/client_matrix.py

@@ -293,6 +293,7 @@ LANG_RELEASE_MATRIX = {
             ("v1.57.2", ReleaseInfo(runtimes=["go1.19"])),
             ("v1.58.3", ReleaseInfo(runtimes=["go1.19"])),
             ("v1.59.0", ReleaseInfo(runtimes=["go1.19"])),
+            ("v1.60.0", ReleaseInfo(runtimes=["go1.19"])),
         ]
     ),
     "java": OrderedDict(