Enable all sprig functions in templates

[endorama]

Non hermetic functions are defined as "impure" functions. The list is
available here: https://github.com/Masterminds/sprig/blob/581758eb7d96ae4d113649668fa96acc74d46e7f/functions.go#L70

We enable them mainly due to date related functions that are very
beneficial to template developers.

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2023-02-16T10:19:50.293+0000

• Duration: 3 min 48 sec

Test stats 🧪

Test	Results
Failed	0
Passed	65
Skipped	0
Total	65

🤖 GitHub comments

Expand to view the GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.

[aspacca]

I'd would be nice if we can add timeDuration directly to sprig in the future

[endorama]

I can work in submitting this function to the library, but is not clear to me which is the expected usage. sprig already provides dateModify function, how would this be different?

[aspacca]

dateModify, mustDateModify
The dateModify takes a modification and a date and returns the timestamp.

it is unclear to me if it returns a time.Time, what's exactly a "timestamp"? :)
we can test anyway, if so, no need, since we can have

{{- $durationInSecond := generate "durationInSecond" }}
{{- $durationString := cat $durationInSecond "s" | nospace }}
{{- $modifiedTime := $timeField | dateModify $durationString }}
{{ $modifiedTime.Format "2006-01-02T15:04:05.999999Z07:00" }}

otherwise we need a function to generate a time.Duration from an int or string (I could not find any in sprig), since we don't have anything in the fields type that generates a time.Duration (and we probably cannot have, since the type comes from package spec)

[aspacca]

I think you need to merge main on the branch @endorama