Bump symfony (v3.4.23 => v3.4.28) and jms/serializer (1.13.0 => 1.14.0)

[phil-davis]

composer update
Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 0 installs, 4 updates, 0 removals
  - Updating jms/serializer (1.13.0 => 1.14.0): Downloading (100%)         
  - Updating symfony/debug (v3.4.23 => v3.4.28): Loading from cache
  - Updating symfony/console (v3.4.23 => v3.4.28): Loading from cache
  - Updating symfony/process (v3.4.23 => v3.4.28): Loading from cache
Writing lock file
Generating autoload files

[codecov]

Codecov Report

Merging #476 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #476   +/-   ##
=========================================
  Coverage     55.83%   55.83%           
  Complexity      291      291           
=========================================
  Files            17       17           
  Lines           942      942           
=========================================
  Hits            526      526           
  Misses          416      416

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 97690f6...9c54976. Read the comment docs.

[codecov]

Codecov Report

Merging #476 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #476   +/-   ##
=========================================
  Coverage     55.83%   55.83%           
  Complexity      291      291           
=========================================
  Files            17       17           
  Lines           942      942           
=========================================
  Hits            526      526           
  Misses          416      416

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 36eedea...2f6ae54. Read the comment docs.

[phil-davis]

@DeepDiver1975 or anybody - this should be an easy review.

[patrickjahns]

LGTM