Standardize format reported by cdat_info.version()

[durack1]

I've been using cdat_info.version to keep track of the cdat installed used for analysis. The output of this command has been varied through time, and I get the following output:

v2.6: >>> cdat_info.version()
['', '2.6']
v2.8: >>> cdat_info.version()
['', 'v2.8']
nightly: >>> cdat_info.version()
['2', '6', '42', 'g910814b']

It would be great to standardize this, so full releases are numeric only e.g.2.10 (so lose the leading v in v2.8 above) and keep the nightly tag intact showing major, minor, commit, hash

[doutriaux1]

@dnadeau4 we need to update cdat_info on conda-forge it's using an old string. We should move the build to use the uv-cdat repo to get correct info.