.github: Checks uses Makefile to run golangci-lint

For anything we run as PR checks it should always be straightforward to
recreate any failure locally in a development environment, so instead of
using the golangci/golangci-lint-action GitHub action (whose behavior
is nontrivial and annoying to reproduce outside of GitHub Actions) we'll
just use our existing Makefile target as part of the check run, matching
how we deal with most other similar concerns in this GitHub Actions
workflow.

Signed-off-by: Martin Atkins <mart@degeneration.co.uk>

.github/workflows/checks.yml

@@ -169,9 +169,12 @@ jobs:
             exit 1
           fi
       - name: "Code linting"
-        uses: golangci/golangci-lint-action@4afd733a84b1f43292c63897423277bb7f4313a9 # v8.0.0
-        with:
-          version: v2.6.0
+        run: |
+          # We use our own Makefile target here, rather than the
+          # golangci/golangci-lint-action action, because it ought to be
+          # possible for someone who encounters a failure here to replicate
+          # exactly the same run in their local development environment.
+          make golangci-lint
       
       - name: "Copyright headers"
         run: |