Try coverage == true matrix ci

Author: mcbarton

.github/workflows/Ubuntu-arm.yml

@@ -253,7 +253,7 @@ jobs:
             clang-runtime: '20'
             cling: Off
             cppyy: Off
-            coverage: On
+            coverage: true
           - name: ubu24-arm-gcc12-clang-repl-19-cppyy
             os: ubuntu-24.04-arm
             compiler: gcc-12