Encode: Follow RFC3339 spec for LocalTime

[jidicula]

Issue: #613

Fixes 2/3 failing subcases for go test -tags testsuite -run TestTOMLTest_Valid_Datetime_Local:

• local
• space

Note that the remaining failing case is addressed by #626.

The fix for this was quite straightforward: RFC3339 specifies a T between date and time, not a as the String() method on LocalDateTime was formatting. See go/time constants for verification: https://pkg.go.dev/time#pkg-constants .

[jidicula]

@pelletier I took the liberty of removing the skip statement for the failing testgen case, but since one of the subcases is covered in #626 and not here, the CI tests will fail. If you inspect the workflow run log, you'll notice that the only failing case is milli (you can see local and space pass if you run go test -v -tags testsuite -run TestTOMLTest_Valid_Datetime_Local). I could:

• drop the skip-removal commit so this PR passes CI,
• rebase onto Decode: preserve nanosecond precision when decoding time #626's branch, or
• do nothing and you can handle the merge order (or cherrypick my commits onto the other PR) to make sure Decode: preserve nanosecond precision when decoding time #626 goes in before this PR.

Let me know what I should do 🙂

[pelletier]

@jidicula do you mind rebasing against v2? Just merged #626.

[jidicula]

@jidicula do you mind rebasing against v2? Just merged #626.

Done!

[pelletier]

Looks like the tests for LocalTime need to be adjust to use T as a separator.

[pelletier]

Thank you for the patch!