build(deps): bump multidict from 4.7.5 to 4.7.6

Bumps [multidict](https://github.com/aio-libs/multidict) from 4.7.5 to 4.7.6.
- [Release notes](https://github.com/aio-libs/multidict/releases)
- [Changelog](https://github.com/aio-libs/multidict/blob/master/CHANGES.rst)
- [Commits](aio-libs/multidict@v4.7.5...v4.7.6)

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

Author: dependabot[bot]

requirements.txt

@@ -8,7 +8,7 @@ googlemaps==4.2.0
 imgurpython==1.1.7
 isodate==0.6.0
 lxml==4.5.0
-multidict==4.7.5
+multidict==4.7.6
 nltk==3.5
 psutil==5.7.0
 py-irclib==0.2.1