Remove deprecated linter, exportloopref, from golangci.yml and replace with copyloopvar

[jtieri]

As of Go 1.22 a fix for the for loop scoping issue has been introduced by making for loops use a per-iteration scope instead of per-loop scope. This means you no longer need to make a copy of loop variables, which makes the existing exportloopref linter unnecessary. golangci-lint has deprecated the linter in favor of a new linter named copyloopvar, which instead looks for unnecessary copy statements in loops.

oss-repo-template-golang/.golangci.yml

Line 20 in 2ff0d86

- exportloopref

Now that Go 1.23 is released we should be using at least 1.22 in our repos.