Instructions for reviews on non-default branch of repo

[mpadge]

Idea from @s3alfisc, implemented in ropensci-review-tools/roreviewapi#27. The ability to do this needs to be documented in Dev Guide. Alex: We encourage community contributions at every opportunity possible. Let us know if you'd like to submit the PR describing this ability. I'd suggest best place would be another dot-point in this list:

dev_guide/softwarereview_author.Rmd

Lines 31 to 40 in aff4bcd

	## The Submission Process
	- Software is submitted for review by [opening a new issue](https://github.com/ropensci/software-review/issues/new/choose) in the software review repository and filling out the template.
	- The template begins with a section which includes several HTML-styled variables (`<!---variable--->`). These are used by our `ropensci-review-bot`, and must be left in place, with values filled between the indicated start and end points, like this:
	```{bash, eval = F}
	<!---variable--->insert value here<!---end-variable>
	```
	- Communication between authors, reviewers and editors will first and foremost take place on GitHub so that the review thread can serve as a full record of the review. You may choose to contact the editor by email or Slack if private consultation is needed (e.g., asking how to respond to a reviewer question). Do not contact reviewers off-thread without asking them in the GitHub thread whether they agree to it.
	- *When submitting a package please make sure your GitHub notification settings make it unlikely you will miss a comment.*
	- Packages are automatically checked on submission by [our `pkgcheck` system](https://docs.ropensci.org/pkgcheck), which will confirm whether or not a package is ready to be reviewed.

which ends up in rendered form here.

[s3alfisc]

I will prepare a PR this weekend!

[maelle]

Thanks @s3alfisc!

We'll also need to update the reviewer guide (installation instructions, a note to search the repo locally and not on GitHub as search is limited to the default branch).

[maelle]

Friendly reminder @s3alfisc 😸

[maelle]

(no worries if you don't have time!)