ios: accept release tag namespace in Fastfile

ios/fastlane/Fastfile

@@ -24,14 +24,15 @@ end
 def release_version
   tag = ENV["SYBIL_VERSION_TAG"]
   tag = ENV["GITHUB_REF_NAME"] if !present?(tag)
+  tag = ENV["GITHUB_REF"].to_s.sub(%r{\Arefs/tags/}, "") if !present?(tag)
   tag = sh("git describe --tags --abbrev=0").strip if !present?(tag)
-  version = tag.to_s.sub(%r{\Arelease/}, "").sub(/\Av/, "")
+  match = tag.to_s.match(%r{\Arelease/ios/v(\d+\.\d+\.\d+)\z})
 
-  unless version.match?(/\A\d+\.\d+\.\d+\z/)
-    UI.user_error!("Release tag must look like v1.2.3; got #{tag.inspect}")
+  unless match
+    UI.user_error!("Release tag must look like release/ios/v1.2.3; got #{tag.inspect}")
   end
 
-  version
+  match[1]
 end
 
 # App Store Connect requires CFBundleVersion to be unique and strictly