Bump mymindstorm/setup-emsdk from 11 to 12

Bumps [mymindstorm/setup-emsdk](https://github.com/mymindstorm/setup-emsdk) from 11 to 12.
- [Release notes](https://github.com/mymindstorm/setup-emsdk/releases)
- [Commits](mymindstorm/setup-emsdk@v11...v12)

---
updated-dependencies:
- dependency-name: mymindstorm/setup-emsdk
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
(cherry picked from commit 6e3dfe5)

Author: dependabot[bot]

.github/workflows/on_PR_meson.yaml

@@ -172,7 +172,7 @@ jobs:
         run: |
           python3 -m pip install meson ninja
       - name: Emscripten
-        uses: mymindstorm/setup-emsdk@v11
+        uses: mymindstorm/setup-emsdk@v12
       - name: Compile
         run: |
           meson setup "${{github.workspace}}/build" --cross-file="${{github.workspace}}/em.txt" --wrap-mode=forcefallback -Ddefault_library=static -Dwarning_level=3 -Dcpp_std=c++20 -DunitTests=disabled