Pin GitHub Actions to hash for supply chain security.

Signed-off-by: SuperQ <superq@gmail.com>

Adds a rate limiting mechanism, that will send HTTP/429 responses once a
defined limit is reached (Token Bucket)

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

Update to Go 1.25, minimum 1.24.0.

Signed-off-by: SuperQ <superq@gmail.com>

Bumps [golang.org/x/time](https://github.com/golang/time) from 0.12.0 to 0.13.0.
- [Commits](golang/time@v0.12.0...v0.13.0)

---
updated-dependencies:
- dependency-name: golang.org/x/time
  dependency-version: 0.13.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.41.0 to 0.42.0.
- [Commits](golang/crypto@v0.41.0...v0.42.0)

---
updated-dependencies:
- dependency-name: golang.org/x/crypto
  dependency-version: 0.42.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Bumps [go.yaml.in/yaml/v2](https://github.com/yaml/go-yaml) from 2.4.2 to 2.4.3.
- [Commits](yaml/go-yaml@v2.4.2...v2.4.3)

---
updated-dependencies:
- dependency-name: go.yaml.in/yaml/v2
  dependency-version: 2.4.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Builds have been stopped in CircleCI, we can remove the config.

Signed-off-by: SuperQ <superq@gmail.com>