Bump exabgp from 4.2.25 to 5.0.8

Bumps [exabgp](https://github.com/Exa-Networks/exabgp) from 4.2.25 to 5.0.8.
- [Release notes](https://github.com/Exa-Networks/exabgp/releases)
- [Changelog](https://github.com/Exa-Networks/exabgp/blob/5.0.8/doc/CHANGELOG.rst)
- [Commits](Exa-Networks/exabgp@4.2.25...5.0.8)

---
updated-dependencies:
- dependency-name: exabgp
  dependency-version: 5.0.8
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

test-requirements.txt

@@ -3,7 +3,7 @@ bitstring
 codecov
 concurrencytest
 debian-inspector
-exabgp==4.2.25
+exabgp==5.0.8
 importlab>=0.3.1
 netifaces
 packaging