Pin Vale to 3.14.2 to fix dicpath resolution regression

Vale 3.15.0 (released 2026-06-12) changed vale sync to create and use
the configured StylesPath instead of falling back to a global styles
directory (vale-cli/vale#1105/#1106). That changed where the ISC
style package's nested styles/ISC/Spelling.yml and styles/dictionaries
land under .github/vale, breaking Spelling.yml's relative `dicpath:
dictionaries` and failing every Spelling & Styles run since with
"unable to resolve dicpath" - unrelated to any PR's content. 3.14.2
was the last version where sync resolved dicpath correctly.

Author: rrrutledge

.github/workflows/vale.yml

@@ -27,3 +27,4 @@ jobs:
         vale_flags: "--glob=*.md"
         filter_mode: added
         debug: true
+        version: 3.14.2