build(deps): bump libmozevent from 1.1.17 to 1.1.18 in /events (#1366)

Bumps [libmozevent](https://github.com/mozilla/libmozevent) from 1.1.17 to 1.1.18.
- [Release notes](https://github.com/mozilla/libmozevent/releases)
- [Commits](https://github.com/mozilla/libmozevent/compare/1.1.17...1.1.18)

---
updated-dependencies:
- dependency-name: libmozevent
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

events/requirements.txt

@@ -4,7 +4,7 @@ aioredis==2.0.1
 json-e==4.4.3
 jsonschema==4.16.0
 libmozdata==0.1.83
-libmozevent==1.1.17
+libmozevent==1.1.18
 python-hglib==2.6.2
 pytoml==0.1.21
 pyyaml==6.0