[build] Harden CI/CD pipeline (#15387)

* NOTE: the release workflows' new handling of secrets
  may be a breaking change for forks that are using any secrets
  other than GPG_SIGNING_KEY or ARCHIVE_REPO_TOKEN.

  Previously, the release workflow would try to resolve a token
  secret name based on the `target` or `source` input,
  e.g. NIGHTLY_ARCHIVE_REPO_TOKEN or CUSTOM_ARCHIVE_REPO_TOKEN,
  and then fall back to using the ARCHIVE_REPO_TOKEN secret if the
  resolved token secret name was not found in the repository.

  This behavior has been replaced by the release workflow
  always using the ARCHIVE_REPO_TOKEN secret as the token
  for publishing releases to any external archive repository.

* Add zizmor CI job for auditing workflows

* Pin all actions to commit hashes instead of symbolic references

* Explicitly set GITHUB_TOKEN permissions at the job level

* Use actions/checkout with `persist-credentials: false` whenever possible

* Remove/replace template expansions in workflow scripts

* Remove all usage of actions/cache from build/release workflows

* Remove the cache-warmer.yml workflow

* Remove the unused download.yml workflow

* Set concurrency limits for any workflows that are triggered by PRs

* Avoid loading the entire secrets context

* Replace usage of `secrets: inherit` with explicit `secrets:` blocks

* Pin all external docker images to hash that are used by the build workflow

* Explicitly set `shell: bash` for some steps to avoid pwsh or set pipefail

* Ensure any pwsh steps will fail on non-zero exit codes

Authored by: bashonly

.github/workflows/issue-lockdown.yml

@@ -10,7 +10,7 @@ jobs:
     name: Issue Lockdown
     if: vars.ISSUE_LOCKDOWN
     permissions:
-      issues: write
+      issues: write  # Needed to lock issues
     runs-on: ubuntu-latest
     steps:
       - name: "Lock new issue"