Update version for podspec to not include dot (#6111)

Protobuf.podspec

@@ -5,7 +5,7 @@
 # dependent projects use the :git notation to refer to the library.
 Pod::Spec.new do |s|
   s.name     = 'Protobuf'
-  s.version  = '3.8.0-rc.1'
+  s.version  = '3.8.0-rc1'
   s.summary  = 'Protocol Buffers v.3 runtime library for Objective-C.'
   s.homepage = 'https://github.com/protocolbuffers/protobuf'
   s.license  = '3-Clause BSD License'

update_version.py

@@ -220,7 +220,7 @@ def UpdateObjectiveC():
   RewriteTextFile('Protobuf.podspec',
     lambda line : re.sub(
       r"^  s.version  = '.*'$",
-      "  s.version  = '%s'" % GetFullVersion(rc_suffix = '-rc.'),
+      "  s.version  = '%s'" % GetFullVersion(rc_suffix = '-rc'),
       line))