Do not index sample programs that do not correspond to a valid project

[rzuckerm]

I fixed #68 . I chose to just ignore a bad sample program name and move on as opposed to crashing. There will be an error in the log:

Could not find a project for <file_name> with name <url> in <project_names>

Also, updated the GitHub actions to fix this warning, for example:
test (3.11)

The following actions uses node12 which is deprecated and will be forced to run on node16: 
actions/checkout@v2, actions/setup-python@v2.

[jrg94]

Thank you! You're quick.