auto: increment master version to 16.0.56

chore(android): Reduce Toast notification noise

Co-authored-by: Marc Durdin <marc@durdin.net>

auto: increment master version to 16.0.55

chore(core): emcc off path for linux

fix(linux): Allow downgrades for installing build deps

chore(linux): Update debian changelog 🍒

chore: update core/ label

Merge pull request #7000 from keymanapp/chore/developer/keymanweb-compiler-remove-unused-dependencies

chore(developer): remove unused dependencies from KeymanWeb compiler 🛩

chore(core): rename json.hpp to jsonpp.hpp 🛩

auto: increment master version to 16.0.54

feat(linux): Dockerfile for linux builder

When install the keyman-build-deps_*.deb file it can happen that
we end up with a lower version number than what we previously
built. This change allows downgrades so that the build dependencies
can be installed.

(cherry picked from commit f2b12771)

- add Dockerfile in linux/Dockerfile, referencing linux/debian/control
- add docs in docs/build/linux-ubuntu.md

Fixes: #7102

auto: increment master version to 16.0.53

fix(linux): Remove wrong `ok_for_single_backspace` method

fix(android/engine): Lower the max height for landscape orientation

The implementation of `ok_for_single_backspace` checked the current
action_item multiple times. However, we already know that that
item is `KM_KBP_IT_BACK` because the only place this method gets
called is from the `process_backspace_action` method. So basically
this method always returns `FALSE`. "Fixing" this method to check
the next action_items makes things fail.

Removing this method since it doesn't do anything except burn
processing cycles...

Fixes #5614.

auto: increment master version to 16.0.52

feat(common): add parameter variable support to `builder_` functions

fix(windows): Add invalidate context action to non-updatable parse

chore: Change platform advocates per discussion

fix(android): verify browser before starting activity

auto: increment master version to 16.0.51