fix: ISO8601 duration wouldn't parse for valid fractional values

[Kshitiz1403]

Previously, the library utilized a parsing library for ISO8601 durations that parsed durations into integers only. This caused issues with durations containing fractional values, such as "PT0.5S", which are valid ISO8601 strings but failed to parse due to the limitation of the previous library.

In this commit, I've replaced the outdated parsing library with a more robust alternative.

The new library properly handles fractional values, ensuring accurate parsing of ISO8601 duration strings, including cases like "PT0.5S". This update enhances the functionality and reliability of the library by accommodating a broader range of ISO8601 duration formats. Additionally, it ensures compatibility with modern standards and improves the overall usability of the library.

[spolti]

The ci issue should be addressed after we merge this https://github.com/serverlessworkflow/sdk-go/pull/200

[Kshitiz1403]

@spolti Any ETA by which this can be merged?

[ricardozanini]

@Kshitiz1403 can you please rebase?

[Kshitiz1403]

Rebased

[Kshitiz1403]

Fixed failing test cases

[ricardozanini]

@Kshitiz1403 can you please sign your commits? Just squash and sign and we can move on.

[Kshitiz1403]

@ricardozanini Can we proceed to the merge?

[ricardozanini]

@Kshitiz1403 sorry I missed this one. Sure thing! Many thanks!

[ricardozanini]

Next time, you can ping me earlier, no problem!!

[Kshitiz1403]

@ricardozanini Can we also create a release?

[Kshitiz1403]

@ricardozanini Just a side note, do you know of any serverless workflow adaption for temporal workflows?

[ricardozanini]

@Kshitiz1403 no, I'm not familiar with this technology.