Merge pull request godotengine#75 from akien-mga/ci-use-linux-sdk

CI: Use our own Linux SDK to maximize glibc compatibilty

CI: Mono 6.12.0.182, Android 32 and other updates

Mono: Bump to 6.12.0.179

Mono: Bump to 6.12.0.178

Mono: Bump to 6.12.0.177

CI: Bump old ubuntu version to ubuntu-18.04

The ubuntu-16.04 runners have been removed from GitHub Actions.

Merge pull request godotengine#43 from akien-mga/mono-6.12.0.147

CI: Build with Mono 6.12.0.147

CI: Build with Mono 6.12.0.144 + other env updates

Update env components to these versions:

- Python 3.9
- Pin NDK to 21.4.7075529 as done by Godot

Not updating Android API level to 30 yet as some feature work is needed in
Godot to support new requirements.

Mono 6.12.0.144 is still a Preview release, but contrarily to 6.12.0.122,
it has a successful Windows build. It also theoretically finalizes support
for Apple M1, so we can attempt using it to build Mono for that arch.

CI: Build with Mono 6.12.0.122 (stable)

Upgrades us to the current stable release.
Further work is done in Preview on Apple Silicon support but we'll look into this
after the Godot 3.3 release.

Merge pull request godotengine#29 from akien-mga/wasm-apply-m2n_tramp…

…olines_hook

WASM: Apply m2n_trampolines_hook patch added in 0e31293