Use easimon/maximize-build-space for the upload_assets.yml workflow

(renamed from generate_assets.yml)

Hope it does not run out of disk space again for our 22 scenarios!

Update CHANGELOG.md for v1.2.2 release

Add CHANGELOG.md to document major changes (e.g. scenario renames)

Fixes #78

Merge pull request #70 from DamonU2/remove-duncan

Remove duncan

Merge pull request #42 from DamonU2/georgiastrait-valdesbois-files

Files added and updated with new scenarios

Merge pull request #5 from OpenDRR/dev_tiegan

Running Leech River on dev_tiegan