Bump wand from 0.6.6 to 0.6.7 in /Backend

Bumps [wand](https://github.com/emcconville/wand) from 0.6.6 to 0.6.7.
- [Release notes](https://github.com/emcconville/wand/releases)
- [Changelog](https://github.com/emcconville/wand/blob/master/docs/changes.rst)
- [Commits](emcconville/wand@0.6.6...0.6.7)

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

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

Backend/requirements.txt

@@ -8,4 +8,4 @@ uuid==1.30
 mysql-connector-python==8.0.27
 cryptography==3.4.8
 pycryptodome==3.11.0
-Wand==0.6.6
+Wand==0.6.7