Adding upstream version 2.52.6.

Signed-off-by: Daniel Baumann <daniel@debian.org>

.github/workflows/linter.yml

@@ -0,0 +1,28 @@
+# Adapted from https://github.com/golangci/golangci-lint-action/blob/b56f6f529003f1c81d4d759be6bd5f10bf9a0fa0/README.md#how-to-use
+
+name: golangci-lint
+on:
+  push:
+    branches:
+      - v2
+  pull_request:
+permissions:
+  contents: read
+
+jobs:
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          # NOTE: Keep this in sync with the version from go.mod
+          go-version: "1.20.x"
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v3
+        with:
+          # NOTE: Keep this in sync with the version from .golangci.yml
+          version: v1.51.0