Build PHP with jpeg support.

[kyrofa]

This PR fixes #24 by building PHP with jpeg support, which means Nextcloud can now generate thumbnails and previews. Please test with the following:

$ sudo snap install nextcloud --edge

Upload .jpg and .png images, and verify that thumbnails are generated. Also verify that, when selecting them, previews are successfully shown.

[oparoz]

Quick question, can we navigate between release channels or is a channel considered a new snap?

[oparoz]

# sudo snap install nextcloud --edge
error: cannot install "nextcloud": snap "nextcloud" already installed

So how do we test this release without losing the data?

[kyrofa]

Quick question, can we navigate between release channels or is a channel considered a new snap?

This isn't all finished yet, but eventually you'll be able to refresh back and forth. For now, you can refresh to a newer revision and then revert back. To change channels, you can use snap refresh, like so:

$ sudo snap refresh nextcloud --edge

Then when you're done testing, you can revert back the previous revision with:

$ sudo snap revert nextcloud

Again, eventually you'll just be able to refresh back to stable (or whatever), but that's not yet finished. Note that I don't really recommend doing this on production data.

[oparoz]

Ah, thanks. None of the usual keywords such as update or upgrade were available, so I felt a bit lost :)

[oparoz]

Tested with JPG and PNG. Works 👍