chore(deps) bump luacheck from 0.25.0 to 0.26.0
chore(deps) bump luacheck from 0.25.0 to 0.26.0

### Summary

Bumps `luacheck` development dependency from 0.25.0 to 0.26.0.

#### New Features

* Add "unused hint" flag — @javierguerragiraldez
  Function arguments that start with a single underscore get an "unused hint".
  Leaving them unused doesn't result in a warning.
  Using them, on the other hand, is a new warning (№ 214).
* Add hook to enable Luacheck for use in pre-commit — @mblayman
* Warn on error-prone and unnecessary negations — @arichard4
  Two new warnings (№ 581 and 582) flag error-prone operator orders.
* Add Dockerfile implementation — @MartinBroers
  A 6.34MB containerized image with everything needed to run the linter.
  Build your own or pull prebuilt images from GHRC.
* Setup repository for use *as* a GitHub Action — @alerque
  Lint your repositories using GitHub Action workflows with just a single `uses:` step.

#### Fixes

* Don't mark variables as accessed if only references are circular — @arichard4
* Make test suite Lua 5.4 compatible — @alerque
* Correct small issues in documentation — various

#### Miscellaneous

* Overhaul CI workflows for testing, linting, building, and releasing — @alerque
* Update URLs and documentation reflecting new repository home — @lunarmodules

Kong/kong,Kong/kong,Kong/kong