Bump sidekiq from 6.5.10 to 7.2.2 in /backend (#746)

Bumps [sidekiq](https://github.com/sidekiq/sidekiq) from 6.5.10 to 7.2.2.
- [Changelog](https://github.com/sidekiq/sidekiq/blob/main/Changes.md)
- [Commits](sidekiq/sidekiq@v6.5.10...v7.2.2)

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

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

backend/Gemfile

@@ -31,7 +31,7 @@ gem "omniauth-facebook", "3.0.0"
 gem "colored"
 
 # Background jobs
-gem "sidekiq", "~> 6.5"
+gem "sidekiq", "~> 7.2"
 
 # Structured seed data
 gem "seedbank"

backend/Gemfile.lock

@@ -348,7 +348,8 @@ GEM
       thor (~> 1.0)
     rainbow (3.1.1)
     rake (13.1.0)
-    redis (4.8.1)
+    redis-client (0.21.1)
+      connection_pool
     regexp_parser (2.9.0)
     request_store (1.5.0)
       rack (>= 1.4)
@@ -397,10 +398,11 @@ GEM
       rake (>= 10.0)
     shoulda-matchers (6.2.0)
       activesupport (>= 5.2.0)
-    sidekiq (6.5.10)
-      connection_pool (>= 2.2.5, < 3)
-      rack (~> 2.0)
-      redis (>= 4.5.0, < 5)
+    sidekiq (7.2.2)
+      concurrent-ruby (< 2)
+      connection_pool (>= 2.3.0)
+      rack (>= 2.2.4)
+      redis-client (>= 0.19.0)
     simplecov (0.22.0)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
@@ -508,7 +510,7 @@ DEPENDENCIES
   ruby-progressbar
   seedbank
   shoulda-matchers
-  sidekiq (~> 6.5)
+  sidekiq (~> 7.2)
   simplecov
   standardrb
   symmetric-encryption