build: bump to Go 1.21 (backport #17333)

[mergify]

This is an automatic backport of pull request #17333 done by Mergify.
Cherry-pick of f0030e0 has failed:

On branch mergify/bp/release/v0.50.x/pr-17333
Your branch is up to date with 'origin/release/v0.50.x'.

You are currently cherry-picking commit f0030e0e6.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   .github/workflows/build.yml
	modified:   .github/workflows/codeql-analysis.yml
	modified:   .github/workflows/dependabot-update-all.yml
	modified:   .github/workflows/dependencies-review.yml
	modified:   .github/workflows/lint.yml
	modified:   .github/workflows/release-confix.yml
	modified:   .github/workflows/release-cosmovisor.yml
	modified:   .github/workflows/release.yml
	modified:   .github/workflows/sims-045.yml
	modified:   .github/workflows/sims-046.yml
	modified:   .github/workflows/sims-047.yml
	modified:   .github/workflows/sims-nightly.yml
	modified:   .github/workflows/sims.yml
	modified:   .github/workflows/test.yml
	modified:   Dockerfile
	modified:   README.md
	modified:   collections/go.mod
	modified:   contrib/images/simd-dlv/Dockerfile
	modified:   contrib/images/simd-env/Dockerfile
	modified:   go.mod
	modified:   go.sum
	modified:   go.work.example
	modified:   simapp/go.mod
	modified:   simapp/go.sum
	modified:   tests/go.mod
	modified:   tests/go.sum
	modified:   tools/confix/go.mod
	modified:   tools/confix/go.sum
	modified:   tools/cosmovisor/go.mod
	modified:   tools/cosmovisor/go.sum
	modified:   tools/hubl/go.mod
	modified:   tools/hubl/go.sum
	modified:   x/circuit/go.mod
	modified:   x/circuit/go.sum
	modified:   x/evidence/go.mod
	modified:   x/evidence/go.sum
	modified:   x/feegrant/go.mod
	modified:   x/feegrant/go.sum
	modified:   x/nft/go.mod
	modified:   x/nft/go.sum
	modified:   x/tx/go.mod
	modified:   x/tx/go.sum
	modified:   x/upgrade/go.mod
	modified:   x/upgrade/go.sum

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   .github/workflows/sims-050.yml
	deleted by us:   .github/workflows/starship-tests.yml
	both modified:   collections/go.sum
	both modified:   contrib/devtools/Dockerfile
	deleted by us:   flake.nix
	deleted by us:   tests/starship/tests/go.mod
	deleted by us:   tests/starship/tests/go.sum

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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