Bump versions for relase

Bump versions

Fixing Game Render Box for flutter >= 1.25

Release v1.0.0-rc6 (flame-engine#639)

Bump versions and fix lint issues (v0.x) (flame-engine#599)

Bump version for rc5

bumping version

Merge pull request flame-engine#574 from flame-engine/develop

Flame 1.0.0-rc3

Bump versions for rc2 release

Merge pull request flame-engine#515 from flame-engine/develop

0.28.0 release