run tests on 0.12 _and_ 0.13 (typst-community#32)

Author: SillyFreak

.github/workflows/tests.yml

@@ -15,6 +15,8 @@ jobs:
         typst-version:
           - typst: 0.12
             tytanic: 0.1
+          - typst: 0.13
+            tytanic: 0.2
             # the docs don't need to build with all versions supported by the package;
             # the latest one is enough
             doc: true