Update meson_ci.yml

Author: dreamer-coding

.github/workflows/meson_ci.yml

@@ -247,7 +247,7 @@ jobs:
             -w /workspace \
             ${GITHUB_REPOSITORY}:${{ matrix.distro }} \
             /bin/bash -c "
-              meson setup builddir --fatal-meson-warnings -Dwerror=true -Dwith_test=enabled -Dwarning_level=3 -Dc_std=c18
+              meson setup builddir --fatal-meson-warnings -Dwerror=true -Dwith_test=enabled -Dwarning_level=3 -Dc_std=c17
               meson compile -C builddir
               meson test -C builddir -v"