bug(http): random NPE on RR start

[rustatian]

Reason for This PR

ref: roadrunner-server/roadrunner-plugins#143

Description of Changes

• Fix bug in the RR-plugins.
• Update dependencies.

License Acceptance

By submitting this pull request, I confirm that my contribution is made under the terms of the MIT license.

PR Checklist

[Author TODO: Meet these criteria.]
[Reviewer TODO: Verify that these criteria are met. Request changes if not]

• All commits in this PR are signed (git commit -s).
• The reason for this PR is clearly provided (issue no. or explanation).
• The description of changes is clear and encompassing.
• Any required documentation changes (code and docs) are included in this PR.
• Any user-facing changes are mentioned in CHANGELOG.md.
• All added/changed functionality is tested.

[codecov]

Codecov Report

Merging #141 (6610975) into master (3b4b35e) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #141   +/-   ##
=======================================
  Coverage   43.73%   43.73%           
=======================================
  Files          12       12           
  Lines         567      567           
=======================================
  Hits          248      248           
  Misses        308      308           
  Partials       11       11           

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