`task export` incorrectly formats numeric values if they are not actually numeric

The basic process and the error message is thus:
```
$ task export > all-tasks.json
$ pacman -Syu task
... installs task 3.0.0 ...
$ task import all-tasks.json
Importing 'all-tasks.json'
Error: missing ']' at position 1
```

Output of `task diag`:

```
task 2.6.2
Platform: Linux

Compiler
Version: 12.2.1 20230201
Caps: +stdc +stdc_hosted +LP64 +c8 +i32 +l64 +vp64 +time_t64
Compliance: C++17

Build Features
Commit: 7400e6ed6
CMake: 3.26.0
libuuid: libuuid + uuid_unparse_lower
libgnutls: 3.8.0
Build type: release

Configuration
File: /home/hearth/.taskrc (found), 4753 bytes, mode 100644
Data: /home/hearth/.task (found), dir, mode 40777
Locking: Enabled
GC: Enabled
Server:
CA: -
Certificate: -
Key: -
Trust: strict
Ciphers: NORMAL
Creds:

Hooks
System: Enabled
Location: /home/hearth/.task/hooks
(-none-)

Tests
Terminal: 302x51
Dups: Scanned 4850 tasks for duplicate UUIDs:
No duplicates found
Broken ref: Scanned 4850 tasks for broken references:
No broken references found
```

So... I see in another git issue here that it was surprising Arch was upgrading people with no warning. It seems that, actually, something else is going on?

I note that the PKBUILD in the Arch /extra/ repository _looks_ fine to me: https://gitlab.archlinux.org/archlinux/packaging/packages/task/-/blob/main/PKGBUILD?ref_type=heads

So I am not sure what is up here!

I also don't know if this is actually the cause of my issue - it could be something entirely unrelated to the upgrade. I mean, if I am indeed on 2.6.2, import should work as expected for 2.6.2!

My package manager upgraded me without me being aware of breaking changes. So I was actually on whatever the Arch repositories says is 3.0.0 for a while. I didn't notice any breakages whatsoever. Given it seems that 3.0.0 is actually 2.6.2 here, that is probably why...

Current plan of action: build task 3.0.0 myself, and see if task import works without a hitch.

The question I have in case it doesn't, I guess, would be if there's some obvious regex to someone familiar with the relevant .json structure I can run to catch any breakages in the .json. Probably it would be easy to spot with a small file, but I have just shy of 5,000 lines.

Thank you for your work!