fix: pginterval to take iso8601 strings

[davecramer]

this is a work in progress looking for comments on how to deal with things like months > 12 should we rationalize this before sending to the backend?

[AppVeyorBot]

✅ Build pgjdbc 1.0.527 completed (commit 3b5e3466b3 by @davecramer)

[codecov-io]

Codecov Report

Merging #1612 into master will increase coverage by 0.06%.
The diff coverage is 78.26%.

@@             Coverage Diff              @@
##             master    #1612      +/-   ##
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+ Coverage        69%   69.06%   +0.06%     
- Complexity     4010     4040      +30     
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  Files           179      179              
  Lines         16664    16750      +86     
  Branches       2716     2740      +24     
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+ Hits          11499    11569      +70     
- Misses         3907     3916       +9     
- Partials       1258     1265       +7

[RhodiumToad]

No particular reason to normalize interval parts; the backend just stores months,days,microseconds anyway and converts to those.

[davecramer]

@RhodiumToad In general I'd like to be able to retrieve what we send. If we have something like 30 months when we get it back it will be different. Not sure that matters, and not sure I want to go to the trouble to make it work. Thanks for your feedback.

[AppVeyorBot]

✅ Build pgjdbc 1.0.528 completed (commit 836a4d8647 by @davecramer)

[AppVeyorBot]

✅ Build pgjdbc 1.0.536 completed (commit 4a6edd7e07 by @davecramer)

[AppVeyorBot]

✅ Build pgjdbc 1.0.539 completed (commit 0aab4d03b7 by @davecramer)