chore: prepare for release 3.1.5 (#459)

Author: jaeopt

CHANGELOG.md

@@ -1,7 +1,7 @@
 # Optimizely Objective-C SDK Changelog
 
 ## 3.1.5
-October 6th, 2020
+October 7th, 2020
 
 ### Bug Fixes
 * Explicitly add secondary dependencies into podspecs to fix Xcode 12 build issue. ([#457](https://github.com/optimizely/objective-c-sdk/pull/457))

Scripts/update_version.sh

@@ -129,8 +129,8 @@ do
     printf "\t[${curPodSpec}] Verified podspec: ${releaseSDKVersion}\n"
 done
 
-# check total 17 (= 7 + 10) places replaced
-expTotalCount=17
+# check total 24 (= 7 + 17) places replaced
+expTotalCount=24
 if (( ${countChanges} == ${expTotalCount} ))
 then
     printf "Verified successfully! (podspec version updated in ${expTotalCount} places) \n"