Docstring link fix

Current https://groups.google.com/a/tensorflow.org/g/build/c/SsW98Eo7l3o link in docstring is broken, https://groups.google.com/a/tensorflow.org/d/topic/build/SsW98Eo7l3o/discussion works better.

Originally added by https://github.com/tensorflow/tensorflow/commit/6d7c376df81efecef9ef69ff865b5ae02ad4ab59
diff --git a/configure.py b/configure.py
index ab4a195..4cb6892 100644
--- a/configure.py
+++ b/configure.py
@@ -1221,7 +1221,7 @@
   only, as of 2019-11-19). TensorFlow needs this flag to massively reduce
   compile times, but until 16.4 is officially released, we can't depend on it.
 
-  See also https://groups.google.com/a/tensorflow.org/g/build/c/SsW98Eo7l3o
+  See also https://groups.google.com/a/tensorflow.org/d/topic/build/SsW98Eo7l3o/discussion
 
   Because it's very annoying to check this manually (to check the MSVC installed
   versions, you need to use the registry, and it's not clear if Bazel will be