build failures due to golang version mismatches

[ryepup]

Describe the bug

Daily run is failing: https://github.com/nginx/nginx-directive-reference/actions/runs/20235153300

go: golang.org/x/tools/gopls@latest: golang.org/x/tools/gopls@v0.21.0 requires go >= 1.25 (running go 1.24.6; GOTOOLCHAIN=local)

same as #425

To reproduce

1. cd tools/devtools
2. make devtools-image
3. command fails on installing golang tools

Expected behavior

Command works, making an image that can be used to build the rest of the code.

Your environment

CI pipeline

Add any other context about the problem here.