As discussed in #46, `CollectibleV1` is not a good name for this
contract as we don't want versioning in the naming. To align with other
contracts in this repository, we're renaming this contract to
`CommunityERC721`.
BREAKING CHANGE: Any references to `CollectibleV1` must be replaced with
`CommunityERC721`
Closes#46
This backports Certora CI integration to this repository, resulting in
GitHub Actions being extended to run formal verification on any change
to contracts that comes in via pull requests.