CI: Move up the 5.2.x image to the new release.

Author: thomasvl

.github/workflows/build.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        swift: ["5.2.4-bionic", "5.1.5-bionic", "5.0.3-bionic", "4.2.4"]
+        swift: ["5.2.5-bionic", "5.1.5-bionic", "5.0.3-bionic", "4.2.4"]
         # protobuf_git can reference a commit, tag, or branch
         # commit: "commits/6935eae45c99926a000ecbef0be20dfd3d159e71"
         # tag: "ref/tags/v3.11.4"