Blast example data url is down

[colinthomas-z80]

We should update the blast example to use the data from the more recent taskvine blast example.

While the existing blast executable download is still working, the version may need to be updated to work with the more recent data as well.

[dthain]

@arctangerines would you be interested in fixing this one up?

[arctangerines]

I can do it. Will report back once I am done.