Point gutenberg mobile ref to v1.1.0

[marecar3]

This PR updates the gutenberg-mobile reference to point to the latest release, v1.1.0. No wpandroid integration changes introduced.

The reference is currently pointing to the release/1.1.0 branch on https://github.com/wordpress-mobile/gutenberg-mobile. Relevant PR: [https://github.com/wordpress-mobile/gutenberg-mobile/pull/726).

When that gets merged to gutenberg-mobile master, I'll update the ref here to point to the merge commit.

To test:
The block editor should work as normal.

Update release notes:

• If there are user-facing changes, I have added an item to RELEASE-NOTES.txt.

[peril-wordpress-mobile]

	Warnings
⚠️	PR is not assigned to a milestone.

Generated by 🚫 dangerJS

[mzorz]

Ok, been testing this for a while, tried:

1. writing
2. publishing
3. modifying
4. updating
5. turning airplane mode on/off
6. rotating.
7. opening a large GB post.
8. uploading media in various ways

All of this seems to be generally working 👍

I can see the title height change on my phone although it's minor (not abrupt as it was before the fix).

I had a crash once, when opening a post with an image block I had just uploaded, and rotating the device while the Editor loader spinner was being shown (https://gist.github.com/mzorz/10a4e975ad130141437d485051227ab2). It happened only after switching back to classic on long posts, and it was an OOM that I couldn't really reproduce without doing the Aztec dance so, I'll give it the go.

I noticed that opening a post with any content, then rotating the device, will produce a new action in the undo/redo history. Opened an issue with that wordpress-mobile/gutenberg-mobile#727, as it's not a blocker for this PR.

LGTM

[marecar3]

Thanks @mzorz !

[mzorz]

Re-tested after the hash was updated, all looks good here @marecar3 !