Feat: Multiple selection of media in gutenberg

[dratwas]

In this PR I added the possibility to set multiple media when inserting to the block.
Related gutenberg-mobile PR wordpress-mobile/gutenberg-mobile#1331
To test:
At this moment we don't support gallery block so this change can not be tested without changes in gutenberg-mobile JS bundle. In the future, we will use this functionality to multiple selections of media for the gallery.

• set multiple prop to true in media-upload bloc
• add image/video block - multiple select should be enabled for selecting media from the device or WP Media
• the array of selected media should be passed to the callback function

[pinarol]

I see that this is a draft but the gutenberg-mobile PR looks ready to review. Is this still work in progress? If yes, you might want to mark gutenberg-mobile PR as Not Ready to Review as well, because reviewers won't be able to test it anyway.

[dratwas]

Hi all, this PR is ready. Could you please make a CR?

[pinarol]

Looking pretty good, thanks! 🎉

[pinarol]

Interestingly CI fails with error:

...
^D��^D��Cloning into '.'...
Warning: Permanently added the RSA host key for IP address '192.30.253.113' to the list of known hosts.

agent key RSA SHA256:oEdX/44m2Y1klY5Uq287qOWuWfJrhusv4e5ImKQ5Uhk returned incorrect signature type

warning: Could not find remote branch pull/12404 to clone.
fatal: Remote branch pull/12404 not found in upstream origin
Exited with code 128

@jtreanor maybe you know this, this PR uses another fork. Is this expected?

[jtreanor]

@pinarol Thanks for the heads up. It looks like the CI failure is a configuration issue on our part. A recent change doesn't seem to be working correctly. I will look into a solution for it and update here.

[pinarol]

thank you @jtreanor 👍

[pinarol]

Could you update your branch from latest develop? @dratwas After that CI should be working