fix: allow otel tracing provider in config

[jgraeger]

This PR aims to allow usage of the open telemetry tracing provider of ory/x in oathkeeper. As ory/x has been updated to a recent version in #999, this came down to a small change in the configuration schema.

Related issue(s)

• Fixed Oathkeeper does not respect TRACING_PROVIDER=otel #888

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I am following the contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
  confirm that I got the approval (please contact
  security@ory.sh) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature
  works.
• I have added or changed the documentation.

Further Comments

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #1039 (195462b) into master (f363b3a) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1039   +/-   ##
=======================================
  Coverage   78.70%   78.70%           
=======================================
  Files          83       83           
  Lines        3869     3869           
=======================================
  Hits         3045     3045           
  Misses        554      554           
  Partials      270      270           

Impacted Files	Coverage Δ
api/decision.go	95.55% <ø> (ø)

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[vinckr]

Hello @jgraeger
Congrats on merging your first PR in Ory 🎉 !
Your contribution will soon be helping secure millions of identities around the globe 🌏.
As a small token of appreciation we send all our first time contributors a gift package to welcome them to the community.
Please drop me an email and I will forward you the form to claim your Ory swag!