feat(core): add new pebble functions #6888

[deepPublicGit]

What changes are being made and why?

New pebble functions added:

{{ fileExists(output.download.uri) }} -- returns true if file exists
{{ fileEmpty(output.download.uri) }} -- returns true if file content is blank

closes #6888

[anna-geller]

let's make sure to add those 3 functions to the second table here https://github.com/kestra-io/kestra/blob/develop/ui/src/assets/documentations/basic.md#pebble-templating -- can you do that @deepPublicGit?

• fileSize
• fileExists
• fileEmpty

[deepPublicGit]

sure!

let's make sure to add those 3 functions to the second table here https://github.com/kestra-io/kestra/blob/develop/ui/src/assets/documentations/basic.md#pebble-templating -- can you do that @deepPublicGit?

* fileSize

* fileExists

* fileEmpty

[deepPublicGit]

Updated the docs

[deepPublicGit]

Thanks @loicmathieu, changes made as per your suggestions

[loicmathieu]

LGTM, thanks.