ci: mcpp 2026.8.26.1 -> 2026.8.26.2 (#11)

Released and indexed. Verifies this repo against the published build rather
than against a branch.

Author: Sunrisepeak

.github/workflows/ci.yml

@@ -33,7 +33,7 @@ env:
   # A version verified to build these packages, not a measured minimum. The pin
   # exists for reproducibility rather than because an older mcpp is known to
   # fail.
-  MCPP_VERSION: 2026.8.26.1
+  MCPP_VERSION: 2026.8.26.2
   XLINGS_VERSION: v2026.8.17.2
   XLINGS_NON_INTERACTIVE: '1'