chore: Prepare for 0.13.0 development

[andygrove]

Which issue does this PR close?

N/A

Rationale for this change

Now that the release branch branch-0.12 is created, main is now for 0.13 development

What changes are included in this PR?

• Bump maven version from 0.12.0-SNAPSHOT to 0.13.0-SNAPSHOT
• Update Spark/Iceberg diffs accordingly
• Bump Cargo version from 0.12.0 to 0.13.0 and ran cargo update
• Update user guide publishing scripts

How are these changes tested?

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.09%. Comparing base (f09f8af) to head (9c524ce).
⚠️ Report is 718 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2809      +/-   ##
============================================
+ Coverage     56.12%   59.09%   +2.97%     
- Complexity      976     1475     +499     
============================================
  Files           119      165      +46     
  Lines         11743    15065    +3322     
  Branches       2251     2507     +256     
============================================
+ Hits           6591     8903    +2312     
- Misses         4012     4895     +883     
- Partials       1140     1267     +127     

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[mbutrovich]

Thanks @andygrove! Are we missing diffs in dev/diffs/iceberg?

[andygrove]

Thanks @andygrove! Are we missing diffs in dev/diffs/iceberg?

Thanks, not sure how those got missed. I updated them.

[comphead]

Thanks @andygrove and @mbutrovich

[mbutrovich]

LGTM, thanks @andygrove!