CI: Bump Crystal version matrix

- 1.12.1 -> 1.12.2
- 1.13.2 -> 1.13.3
- 1.14.0 -> 1.14.1
- 1.15.0 -> 1.15.1
- Add 1.16.2

.github/workflows/ci.yml

@@ -38,10 +38,11 @@ jobs:
       matrix:
         stable: [true]
         crystal:
-          - 1.12.1
-          - 1.13.2
-          - 1.14.0
-          - 1.15.0
+          - 1.12.2
+          - 1.13.3
+          - 1.14.1
+          - 1.15.1
+          - 1.16.2
         include:
           - crystal: nightly
             stable: false