Add scala steward

.github/labeler.yml

@@ -0,0 +1,14 @@
+version: 1
+labels:
+  - label: "automerge"
+    authors: ["softwaremill-ci"]
+    files:
+      - "build.sbt"
+      - "project/Versions.scala"
+      - "project/plugins.sbt"
+  - label: "dependency"
+    authors: ["softwaremill-ci"]
+    files:
+      - "build.sbt"
+      - "project/Versions.scala"
+      - "project/plugins.sbt"

.github/workflows/ci.yml

@@ -71,3 +71,41 @@ jobs:
           version: "v${{ env.VERSION }}"
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  # `automerge` label is attached iff there is exactly one file changed by steward and this file belongs to a
+  # whitelist specified by `labeler.yml`
+  label:
+    name: Attach automerge label
+    # only for PRs by softwaremill-ci
+    if: github.event.pull_request.user.login == 'softwaremill-ci'
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 2
+      # count number of files changed
+      - name: Count number of files changed
+        id: count-changed-files
+        run: |
+          N=$(git diff --name-only -r HEAD^1 HEAD | wc -w)
+          echo "changed_files_num=$N" >> $GITHUB_OUTPUT
+      - name: Launch labeler
+        # skip if more than one file changed
+        if: steps.count-changed-files.outputs.changed_files_num == 1
+        uses: srvaroa/labeler@master
+        env:
+          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+
+  auto-merge:
+    name: Auto merge
+    # only for PRs by softwaremill-ci
+    if: github.event.pull_request.user.login == 'softwaremill-ci'
+    needs: [ ci, mima, label ]
+    runs-on: ubuntu-22.04
+    steps:
+      - id: automerge
+        name: automerge
+        uses: "pascalgn/automerge-action@v0.15.6"
+        env:
+          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+          MERGE_METHOD: "squash"

.github/workflows/scala-steward.yml

@@ -0,0 +1,28 @@
+name: Scala Steward
+
+# This workflow will launch at 00:00 every day
+on:
+  schedule:
+    - cron: '0 0 * * *'
+  workflow_dispatch:
+
+jobs:
+  scala-steward:
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Set up JDK 11
+        uses: actions/setup-java@v3
+        with:
+          distribution: 'temurin'
+          java-version: 11
+          cache: 'sbt'
+      - name: Launch Scala Steward
+        uses: scala-steward-org/scala-steward-action@v2
+        with:
+          author-name: scala-steward
+          author-email: scala-steward
+          github-token: ${{ secrets.REPO_GITHUB_TOKEN }}
+          repo-config: .scala-steward.conf
+          ignore-opts-files: false