env: do we have llvm-cov

.github/workflows/coverage-linux.yml

@@ -72,7 +72,7 @@ jobs:
         env:
           NODE_OPTIONS: --max-old-space-size=8192
       - name: Report C++
-        run: gcovr --object-directory=out -v --gcov-exclude='.*\b(deps|usr|obj|cctest|embedding)\b' --xml -o ./coverage/coverage-cxx.xml --root=./ --gcov-executable="llvm-cov gcov"
+        run: gcovr --object-directory=out -v --gcov-exclude='.*\b(deps|usr|obj|cctest|embedding)\b' --xml -o ./coverage/coverage-cxx.xml --root=./ --gcov-executable="llvm-cov-18 gcov"
       # Clean temporary output from gcov and c8, so that it's not uploaded:
       - name: Clean tmp
         run: rm -rf coverage/tmp && rm -rf out