Add podspec for C++ (#6404)

diff --git a/update_version.py b/update_version.py
index 311b25c..ddb2480 100755
--- a/update_version.py
+++ b/update_version.py
@@ -250,6 +250,11 @@
       r"^  s.version  = '.*'$",
       "  s.version  = '%s'" % GetFullVersion(rc_suffix = '-rc'),
       line))
+  RewriteTextFile('Protobuf-C++.podspec',
+    lambda line : re.sub(
+      r"^  s.version  = '.*'$",
+      "  s.version  = '%s'" % GetFullVersion(rc_suffix = '-rc'),
+      line))
 
 
 def UpdatePhp():