Update reqwest requirement from =0.8.6 to =0.8.7 (#856)
Update reqwest requirement from =0.8.6 to =0.8.7 (#856)

Updates the requirements on [reqwest](https://github.com/seanmonstar/reqwest) to permit the latest version.
- [Release notes](https://github.com/seanmonstar/reqwest/releases)
- [Changelog](https://github.com/seanmonstar/reqwest/blob/master/CHANGELOG.md)
- [Commits](https://github.com/seanmonstar/reqwest/commits/v0.8.7)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
exonum/exonum,alekseysidorov/exonum,alekseysidorov/exonum,alekseysidorov/exonum,exonum/exonum,exonum/exonum,alekseysidorov/exonum,exonum/exonum