ci: setup workflows for release-1.x branch

.github/workflows/backport.yml

@@ -0,0 +1,26 @@
+name: Backport
+on:
+  pull_request_target:
+    types:
+      - closed
+      - labeled
+
+jobs:
+  backport:
+    name: Backport
+    runs-on: ubuntu-latest
+    # Only react to merged PRs for security reasons.
+    # See https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target.
+    if: >
+      github.event.pull_request.merged
+      && (
+        github.event.action == 'closed'
+        || (
+          github.event.action == 'labeled'
+          && contains(github.event.label.name, 'backport')
+        )
+      )
+    steps:
+      - uses: tibdex/backport@v2
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/ci.yml

@@ -1,5 +1,11 @@
 name: Continuous Integration
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+      - release-1.x
+
 jobs:
   build:
     name: Build

.github/workflows/golangci-lint.yml

@@ -4,8 +4,8 @@ on:
     tags:
       - v*
     branches:
-      - master
       - main
+      - release-1.x
   pull_request:
 jobs:
   golangci:

.github/workflows/release-please.yml

@@ -2,6 +2,8 @@ on:
   push:
     branches:
       - main
+      - release-1.x
+
 name: release-please
 
 jobs:
@@ -18,3 +20,6 @@ jobs:
           # we need to write it to a file that is included in the git tag.
           extra-files: |
             hcloud/hcloud.go
+
+          # Configuration for multiple active release branches
+          default-branch: ${{ github.ref_name }}

MAINTAINERS.md

@@ -0,0 +1,11 @@
+# Maintainers Guide
+
+This guide is intended for _maintainers_.
+
+## Release Branches
+
+All development targets the `main` branch. New releases for the 2.x series are cut from this.
+
+For the 1.x series which will be supported until at least September 1 2023 we also have a `release-1.x` branch where we try to backport all bug fixes.
+
+Backports are done by [tibdex/backport](https://github.com/tibdex/backport). Apply the label `backport release-1.x` to the PRs and once they are merged a new PR is opened.