ci: bump actions/setup-go to v7.0.0 for Node.js 24 runner support

[Sunny (sunnylovestiramisu)]

Summary

This PR bumps actions/setup-go and actions/setup-python to v7.0.0 across the CI and release workflows, removing runner deprecation warnings for Node.js 20.

GitHub Actions runners are deprecating the Node.js 20 execution runtime and forcing actions targeting Node.js 20 onto Node.js 24. While existing workflows are temporarily forced to run under Node.js 24 with deprecation warnings, bumping both actions to v7.0.0 moves them onto native Node.js 24 execution and eliminates all runner deprecation warnings:

• .github/workflows/ci.yaml:
  • actions/setup-go bumped from v5.6.0 (40f1582b2485089dde7abd97c1529aa768e1baff) to v7.0.0 (b7ad1dad31e06c5925ef5d2fc7ad053ef454303e).
  • actions/setup-python bumped from v5.6.0 (a26af69be951a213d495a4c3e4e4022e16d87065) to v7.0.0 (5fda3b95a4ea91299a34e894583c3862153e4b97).
• .github/workflows/release.yaml:
  • actions/setup-go bumped from v5.6.0 (40f1582b2485089dde7abd97c1529aa768e1baff) to v7.0.0 (b7ad1dad31e06c5925ef5d2fc7ad053ef454303e).

With these updates, no actions in ci.yaml or release.yaml target Node.js 20 (actions/checkout is already on v5.1.0 which runs on Node.js 24, and setup-ko / cosign-installer are composite actions). Both v7.0.0 actions maintain drop-in compatibility for all inputs, outputs, and caching behaviors.

Testing

• make verify-gofmt passed.
• hack/verify/boilerplate.sh passed.
• go test -count=1 ./... passed.

[Tomer Glottmann (tomergee)]

The bump is correct and safe. The description is wrong about what it fixes. Two changes before merge.

Blocking: none.

Before merge

1. PR description. The #80 presubmit did not fail because of Node.js 20. The Node.js 20 message is a warning; the action ran on Node.js 24 and the step passed. The job failed at hack/verify/boilerplate.sh: five files in #80 have no license header (clients/python/src/ate_env/backend/__init__.py, clients/python/tests/test_config.py, test_exec_semantics.py, test_fleet_strategies.py, test_fleet_types.py). This PR does not make #80 green. Rewrite the first paragraph: this PR removes the deprecation warning. Add the headers in #80.
2. .github/workflows/ci.yaml:58. actions/setup-python@a26af69… (v5.6.0) also runs on Node.js 20. The same warning shows on the Python job of this PR's own run (38473102364). Bump it in this PR: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0 (tag verified, runs.using: node24). After that, no action in the two workflows targets Node.js 20: checkout v5.1.0 is node24, setup-ko and cosign-installer are composite.

Verified, no action needed

• b7ad1dad… is the v7.0.0 tag and also the v7 major tag; runs.using: node24.
• v7.0.0 has the inputs go-version-file and cache; both call sites are drop-in.
• v6.0.0 changed toolchain selection (actions/setup-go#460). go.mod has go 1.27.0 and no toolchain line, thus the installed Go stays 1.27.0. The Go job on this PR passed.
• v7.0.0 itself is the ESM migration plus @actions/cache 6.2.0; no input changes.

Nit

• Body, "Testing": go test and the verify scripts do not test a workflow change. Name this PR's CI run and the missing warning on the Go job instead.

[Tomer Glottmann (tomergee)]

Both points addressed: the description now says what the PR does, and setup-python is on the verified v7.0.0 pin. CI run 38481020510 has no Node.js 20 warning on either job.