[Repo Assist] ci: update GitHub Actions to Node.js 24-compatible versions

[github-actions]

🤖 This PR was created by Repo Assist, an automated AI assistant.

Summary

Updates GitHub Actions action versions to address Node.js 20 deprecation warnings appearing in CI logs.

Changed files:

Workflow	Before	After
build.yml (build + analyze jobs)	actions/checkout@v3	actions/checkout@v4
build-and-pack-nightly.yml	actions/checkout@v3, actions/setup-dotnet@v2	actions/checkout@v4, actions/setup-dotnet@v4
bump-fcs.yml	actions/checkout@v3, actions/setup-dotnet@v2	actions/checkout@v4, actions/setup-dotnet@v4
release.yml	actions/checkout@v3	actions/checkout@v4

Motivation

Every CI run currently shows this deprecation warning:

Node.js 20 actions are deprecated. The following actions are running on Node.js 20 and may not work as expected: actions/checkout@v3, actions/setup-dotnet@v4 (for v2 instances). Actions will be forced to run with Node.js 24 by default starting June 2nd, 2026.

actions/checkout@v4 and actions/setup-dotnet@v4 are the stable current major versions. auto-merge-main-to-nightly.yml and copilot-setup-steps.yml were already using @v4 variants.

Test Status

No functional changes — only CI infrastructure updates. The changes affect GitHub Actions runner environment versions, not the F# code or test logic.

---

Warning

Protected Files — Push Permission Denied

This was originally intended as a pull request, but the patch modifies protected files. A human must create the pull request manually.

Protected files

• .github/workflows/build-and-pack-nightly.yml

• .github/workflows/build.yml
• .github/workflows/bump-fcs.yml
• .github/workflows/release.yml

The push was rejected because GitHub Actions does not have workflows permission to push these changes, and is never allowed to make such changes, or other authorization being used does not have this permission.

Create the pull request manually

# Download the patch from the workflow run
gh run download 23883457100 -n agent -D /tmp/agent-23883457100

# Create a new branch
git checkout -b repo-assist/eng-update-github-actions-20260402-afa3bc44e4fa35f6 main

# Apply the patch (--3way handles cross-repo patches)
git am --3way /tmp/agent-23883457100/aw-repo-assist-eng-update-github-actions-20260402.patch

# Push the branch and create the pull request
git push origin repo-assist/eng-update-github-actions-20260402-afa3bc44e4fa35f6
gh pr create --title '[Repo Assist] ci: update GitHub Actions to Node.js 24-compatible versions' --base main --head repo-assist/eng-update-github-actions-20260402-afa3bc44e4fa35f6 --repo ionide/FsAutoComplete

Generated by 🌈 Repo Assist, see workflow run. Learn more.

To install this agentic workflow, run

gh aw add githubnext/agentics/workflows/repo-assist.md@e1ecf341a90b7bc2021e77c58685d7e269e20b99