spool support for patches with timedelta coordinates

[d-chambers]

Description

When chunking or spooling patches that have a time coordinate with dtype of timedelta64 (not datetime64) spool.chunk falls over.

Example

from dascore.examples import ricker_moveout
# ricker moveout patch uses time_delta rather than datetime for time coord
patch = ricker_moveout()

spool = dc.spool(patch)
chunk = spool.chunk(time=0.02)  # raises exception.

Expected behavior

Chunking should work fine.

Versions

• OS [e.g. Ubuntu 20.04]:
• DASCore Version [e.g. 0.0.5]:
• Python Version [e.g. 3.10]: