Fix 403 when downloading: Incorrect string slicing

[tonytwostep]

The fix for #8 used the wrong string slicing, leading to it not actually fixing the issue. The conditional at line 39 would never get triggered, so the download_token won't be passed to the request.

Example of change with test string:

endpoint_example_string = "albums/ask1kblkcktmxw9a/dl"

# Existing slice
print(endpoint_example_string[:3])

# Proposal (fixed)
print(endpoint_example_string[-3:])

Output:

# Existing
alb

# Corrected
/dl

Please merge this before tagging a new release since the code currently in the main branch still has broken downloading. Thank you.

[angus-mcmahon]

@tonytwostep #8 relates to the endpoint /dl/:hash.
I mentioned in #9 (comment) that there might be other endpoints that need to be fixed... looks like there is.

Your fix resolves the endpoint example you used, but breaks the hash endpoint.