[CI] Fix release script (#675)

Author: testableapple

fastlane/Fastfile

@@ -75,7 +75,7 @@ lane :release do |options|
     File.write(artifacts_path, JSON.dump(artifacts))
 
     # Set the framework version in SystemEnvironment+Version.swift
-    new_content = File.read(swift_environment_path).gsub!(previous_version_number, release_version).gsub!('-SNAPSHOT', '')
+    new_content = File.read(swift_environment_path).gsub!(previous_version_number, release_version).gsub('-SNAPSHOT', '')
     File.open(swift_environment_path, 'w') { |f| f.puts(new_content) }
 
     # Update sdk sizes