point to CSS branch (#1051)

Task/Issue URL:
https://app.asana.com/0/1204186595873227/1208592742896624/f
iOS PR: 
macOS PR:  duckduckgo/macos-browser#3485
What kind of version bump will this require?: Minor

**Description**:  Updated C-S-S dependency

Package.resolved

@@ -14,8 +14,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/duckduckgo/content-scope-scripts",
       "state" : {
-        "revision" : "6cab7bdb584653a5dc007cc1ae827ec41c5a91bc",
-        "version" : "6.29.0"
+        "revision" : "1733ee59f06f6e725a98cf6cd8322159f59d664b",
+        "version" : "6.31.0"
       }
     },
     {

Package.swift

@@ -51,8 +51,8 @@ let package = Package(
         .package(url: "https://github.com/duckduckgo/TrackerRadarKit", exact: "3.0.0"),
         .package(url: "https://github.com/duckduckgo/sync_crypto", exact: "0.3.0"),
         .package(url: "https://github.com/gumob/PunycodeSwift.git", exact: "3.0.0"),
+        .package(url: "https://github.com/duckduckgo/content-scope-scripts", exact: "6.31.0"),
         .package(url: "https://github.com/duckduckgo/privacy-dashboard", exact: "7.1.1"),
-        .package(url: "https://github.com/duckduckgo/content-scope-scripts", exact: "6.29.0"),
         .package(url: "https://github.com/httpswift/swifter.git", exact: "1.5.0"),
         .package(url: "https://github.com/duckduckgo/bloom_cpp.git", exact: "3.0.0"),
         .package(url: "https://github.com/1024jp/GzipSwift.git", exact: "6.0.1")