Add a workflow to auto-increment the tag (#320)

.github/workflows/tag.yml

@@ -0,0 +1,41 @@
+name: Create Tag and trigger release
+on:
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: "Tag name, defaults to minor increment."
+        required: false
+      sha:
+        description: "Commit SHA to tag. Defaults to latest."
+        required: false
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set the commit SHA
+        id: sha
+        run: echo "::set-output name=commitSha::$(if [ -z "$SHA" ]; then echo $GITHUB_SHA; else echo $SHA; fi)"
+        env:
+          SHA: ${{ github.event.inputs.sha }}
+      - name: Set the tag
+        id: tag
+        run: |
+          last_tag="$(git describe --tags --abbrev=0)"
+          # Parse the version into parts, increment the minor version and reset the patch to 0
+          # Example:
+          # v1.2.3 is parsed into $1 = "v1.", $2 = "2", $3 = ".3"
+          # and concatenated back into v1.3.0
+          new_tag="$(echo "$last_tag" | perl -pe 's/^(v\d+\.)(\d+)(\.\d+)$/$1.($2+1).".0"/e')"
+          echo "::set-output name=newTag::$(if [ -z "$TAG" ]; then echo $new_tag; else echo $TAG; fi)"
+        env:
+          TAG: ${{ github.event.inputs.tag }}
+      - name: Create tag
+        uses: actions/github-script@v5
+        with:
+          script: |
+            github.rest.git.createRef({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              ref: 'refs/tags/${{ steps.tag.outputs.newTag }}',
+              sha: '${{ steps.sha.outputs.commitSha }}'
+            })