Bump STTextView Version (#138)

Bump STTextView version to latest, as it includes a fix for scroll
performance and content rendering in large files.

For more info see this
[discussion](krzyzanowskim/STTextView#12).

Author: denil-ct

Package.swift

@@ -15,7 +15,7 @@ let package = Package(
     dependencies: [
         .package(
             url: "https://github.com/krzyzanowskim/STTextView.git",
-            exact: "0.1.2"
+            exact: "0.4.0"
         ),
         .package(
             url: "https://github.com/CodeEditApp/CodeEditLanguages.git",