### Summary
I'm fixing one or more of the following CI/CD misconfigurations to
improve security. Please feel free to leave a comment if you think the
current permissions for the GITHUB_TOKEN should not be restricted so I
can take a note of it as accepted behaviour.
- Restrict permissions for GITHUB_TOKEN
- Add step-security/harden-runner
- Pin Actions to a full length commit SHA
### Security Fixes
will fix https://github.com/neondatabase/cloud/issues/26141
## Problem
We use ubuntu-latest as a default OS for running jobs. It can cause
problems due to instability, so we should use the LTS version of Ubuntu.
## Summary of changes
The image ubuntu-latest was changed with ubuntu-22.04 in workflows.
## Checklist before requesting a review
- [x] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
## Checklist before merging
- [ ] Do not forget to reformat commit message to not include the above
checklist
## Problem
For PRs from external contributors, we're still running `actionlint` and
`neon_extra_builds` workflows (which could fail due to lack of
permissions to secrets).
## Summary of changes
- Extract `check-permissions` job to a separate reusable workflow
- Depend all jobs from `actionlint` and `neon_extra_builds` workflows on
`check-permissions`
