build(deps): bump libmozevent from 1.1.5 to 1.1.6 in /events (#622)

Bumps [libmozevent](https://github.com/mozilla/libmozdata) from 1.1.5 to 1.1.6.
- [Release notes](https://github.com/mozilla/libmozdata/releases)
- [Commits](https://github.com/mozilla/libmozdata/commits)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: dependabot[bot]

events/requirements.txt

@@ -1,2 +1,2 @@
 -e ../tools #egg=code-coverage-tools
-libmozevent==1.1.5
+libmozevent==1.1.6