GitHub Actions: Fix hendrikmuhs/ccache miss on Build Jupyter Kernel

[cclauss]

The GitHub Action hendrikmuhs/ccache-action is used 8 times and most jobs successfully use that cache. However, 2 jobs Build Jupyter Kernel and Build LPython to WASM raise Saving cache failed warnings at the bottom right of
https://github.com/lcompilers/lpython/actions/runs/9861518999

Save cache using key "sccache-build_jupyter_kernel--2024-07-11T04:38:05.880Z".
Warning: Saving cache failed: Error: Path Validation Error: Path(s) specified in the action for caching do(es) not exist, hence no cache is being saved.

This pull request attempts to fix the cache miss on the Build Jupyter Kernel job.

@hendrikmuhs Your review, please.

[cclauss]

Success. There are no more Saving cache failed warnings at the bottom right of
https://github.com/lcompilers/lpython/actions/runs/9886143386?pr=2773

From the Post Run hendrikmuhs/ccache-action job step of Build Jupyter Kernel:

Cache Size: ~57 MB (60226930 B)
Cache saved successfully

In the Post Run hendrikmuhs/ccache-action job step of Build LPython to WASM:

Not saving cache because no objects are cached.

This pull request has fixed both cache miss warnings but I am unsure how to make Build LPython to WASM actually use the cache.