Add information about R version support

[IndrajeetPatil]

Similar to:
https://www.tidyverse.org/blog/2019/04/r-version-support/

This should go into developer-facing vignette.

More importantly, we should test all supported R versions on GHA to ensure that we actually support these R versions. Currently, we don't do this. We support R >= 3.5, by test only until R >= 3.6 to avoid the headache of dealing with missing R packages on this older version.

P.S. TBH, given that R 3.6.0 was released almost 2.5 years ago (2019-04-26), I wouldn't mind bumping the minimum needed R version to 3.6.

[mattansb]

How many major releases back should we support?

• 4.2 current
• 4.1
• 4.0
• 3.6
• 3.5

So 3.6 doesn't feel that far back to me.

In effectsize I do test on 3.5 without a problem, using skip_if_not_installed() where needed (and I copied the yaml from you, so aren't everyone?)

[IndrajeetPatil]

How many major releases back should we support?

You mean minor, right? (As in major.minor.patch).

I would say four; i.e., R >= 3.6.

[bwiernik]

Agree that 3.6 (two versions older than r-oldrel) is a good back-support line

[IndrajeetPatil]

@strengejacke WDYT?

[strengejacke]

Yeah, I agree. Back to 3.6 should be enough.

[strengejacke]

Maybe we probably shouldn't make this change to insight, as some wider used packages that import insight still support R 3.5?

[IndrajeetPatil]

See my response here.