Add support for shiny express apps

[wch]

Intent

This PR adds support for Shiny express apps.

Type of Change

• Bug Fix
• New Feature
• Breaking Change

Approach

The main change was pretty straightforward. It involves copying the contents of one file from the shiny package, and then adding three lines of code that change the entrypoint and set an environment variable.

However, there were more changes that I made, with some help from @mmarchetti. The use of kwargs = locals(), and passing the kwargs along to RSConnectExecutor(**kwargs) was confusing and caused some problems, so I made the arguments explicit.

Automated Tests

I didn't add any tests.

Directions for Reviewers

This will require a close look to make sure that the extra_args being passed to RSConnectExecutor() contain the correct items. With the previous code, it was extremely difficult to tell which arguments from the kwargs were meant to go to RSConnectExecutor(), and which ones just happened to be along for the ride.

Checklist

• I have updated CHANGELOG.md to cover notable changes.
• I have updated all related GitHub issues to reflect their current state.

[wch]

That there is a type-checking error in CI -- this issue actually existed in the code before but wasn't picked up on by the type checker because it was obscured by passing in the kwargs; now that the arguments are explicit, the type checker is seeing the problem.

The problem is that in deploy_app(), cacert is typed as IO[Any], but then it is passed to RSConnectExecutor(), and the class constructor there expects cacert to be a str.

Looking at the code, I suspect that it should be str in both places, but I don't know for sure.

[wch]

I also didn't update the changelog because there wasn't a section since the previous release. Should I add one?

[github-actions]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
4411	2857	65%	0%	🟢

New Files

File	Coverage	Status
rsconnect/shiny_express.py	26%	🟢
TOTAL	26%	🟢

Modified Files

File	Coverage	Status
rsconnect/main.py	56%	🟢
TOTAL	56%	🟢

updated for commit: d9e230a by action🐍

[karangattu]

Verified that deployments for shiny express app works as expected for connect, shinyapps.io and posit.cloud.
Connect url for deployed app - link
Shinyapps.io url for deployed app - link
Posit.cloud url for deployed app - link

[karangattu]

Tests for deploying shiny express apps via the rsconnect-python package to connect will be added in the next week.

[karangattu]

The tests for this will live in py-shiny and will be merged once rsconnect main has the PR code. All manual tests are done and the feature works as expected. PR can be merged.