feat: add workflow to bump version in ci

Version bumps are done via git tagging, which can be annoying to do locally as I would need to lookup the last release. Instead, automate the actual workflow so that it can be bumped in CI.

Ideally version bumps are done on PR merge and automatically computed, but this workflow is fine for now.

.github/workflows/bump-version.yaml

@@ -0,0 +1,52 @@
+---
+name: "bump-version"
+
+# yamllint disable-line rule:truthy
+on:
+  workflow_dispatch:
+    inputs:
+      bump_type:
+        description: "Bump type"
+        default: "patch"
+        required: true
+        type: choice
+        options:
+          - patch
+          - minor
+          - major
+
+env:
+  GITHUB_ACCESS_TOKEN: ${{ secrets.GH_ACCESS_TOKEN }}
+
+jobs:
+  bump-version:
+    name: bump-version
+    runs-on: ubuntu-22.04
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4.1.4
+        with:
+          fetch-depth: 0
+          token: ${{ env.GITHUB_ACCESS_TOKEN }}
+
+      - name: Get Latest Tag
+        id: latest-tag
+        run: |
+          echo GIT_LATEST_TAG="$(git describe --tags "$(git rev-list --tags --max-count=1)")" >>"$GITHUB_OUTPUT"
+
+      - name: Compute Next Tag
+        id: next-tag
+        uses: docker://ghcr.io/dokku/semver-generator:latest
+        with:
+          bump: ${{ github.event.inputs.bump_type }}
+          input: ${{ steps.latest-tag.outputs.GIT_LATEST_TAG }}
+
+      - name: Create and Push Tag
+        run: |
+          git config --global user.name 'Dokku Bot'
+          git config --global user.email no-reply@dokku.com
+          git tag "$GIT_NEXT_TAG"
+          git push origin "$GIT_NEXT_TAG"
+        env:
+          GIT_NEXT_TAG: ${{ steps.next-tag.outputs.version }}