ci: replace modernize job with golangci linters

Instead of using a standalone modernize (and a separate job), add
modernize and go vet (which should be same-as/similar-to go fix) linters
to golangci-lint config.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

.github/workflows/validate.yml

@@ -52,28 +52,6 @@ jobs:
         run: |
           golangci-lint run --config .golangci-extra.yml --new-from-rev=HEAD~1
 
-  modernize:
-    runs-on: ubuntu-24.04
-    steps:
-      - uses: actions/checkout@v7
-        with:
-          fetch-depth: 2
-      - uses: actions/setup-go@v6
-        with:
-          go-version: stable # modernize@latest may require latest Go.
-      - name: install deps
-        run: |
-          sudo apt -q update
-          sudo apt -qy install libseccomp-dev
-      - name: run go fix
-        run: |
-          go fix ./...
-          git diff --exit-code
-      - name: run modernize
-        run: |
-          go run golang.org/x/tools/go/analysis/passes/modernize/cmd/modernize@latest -fix ./...
-          git diff --exit-code
-
   compile-buildtags:
     runs-on: ubuntu-24.04
     env:
@@ -328,7 +306,6 @@ jobs:
       - get-images
       - keyring
       - lint
-      - modernize
       - release
       - shellcheck
       - shfmt

.golangci.yml

@@ -15,6 +15,8 @@ linters:
   enable:
     - errorlint
     - forbidigo
+    - govet
+    - modernize
     - nolintlint
     - unconvert
     - unparam