Features

• Add custom scopes for access tokens from the metadata service (#633) (0323cf3)

Bug Fixes

• deps: Revert "fix: pin 'aoihttp < 3.7.0dev' (#634)" (#632) (#640) (b790e65)
• pin 'aoihttp < 3.7.0dev' (#634) (05f9524)
• remove checks for ancient versions of Cryptography (#596) (6407258), closes /github.com/googleapis/google-auth-library-python/issues/595#issuecomment-683903062