Adding image/jpeg as a default binary content type

[artkay]

I am working on a small scale image processing API and I need to support both content types - image/jpg and image/jpeg while Chalice allows me to use image/jpg only.
This PR adds exactly one line - the new content type with the e.

[stealthycoin]

Thanks for the pull request @artkay.

The only issue here is that there is a hard limit right now of 25 binary types that can be assigned to an API Gateway REST API. If a new default type is added it can cause projects already at the 25 limit to be pushed to 26, causing a deployment failure. So this change is potentially not a backwards compatible one.

That being said I am not against adding a few more common ones to the default list as long as the version is bumped accordingly and people are warned in the changelog.

Also to be clear you are not blocked, the default list is just for convenience. Chalice supports modifying this list through the app.api.binary_types property which is documented here and here.

For example this would give you the support you need:

from chalice import Chalice
app = Chalice(app_name='app')
app.api.binary_types.append('image/jpeg')

[jamesls]

Yeah, while this does possibly introduce an issue for someone with 25 or more binary content types, it does seem like this is a common enough content type for it to be in the default list.

Perhaps we can also update our docs to suggest that if you're going to modify the binary types that you explicitly control all of them to be protected against new default additions in the future.

[stealthycoin]

I'd be happy to take this one. There is another related change I'd like to make to the docs at the same time.