ci: add semantic-release workflow

https://github.com/semantic-release/semantic-release
https://github.com/semantic-release/semantic-release/blob/master/docs/recipes/github-actions.md
Idea from https://github.com/ahmadnassri/action-dependabot-auto-merge

.github/workflows/release.yml

@@ -0,0 +1,47 @@
+name: Release
+# Release the action on push to master
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+
+    outputs:
+      published: ${{ steps.release.outputs.published }}
+      release-version: ${{ steps.release.outputs.release-version }}
+      release-version-major: ${{ steps.release.outputs.release-version-major }}
+      release-version-minor: ${{ steps.release.outputs.release-version-minor }}
+
+    steps:
+      - uses: actions/checkout@v2
+      - id: release
+        name: semantic-release
+        uses: ahmadnassri/action-semantic-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  alias:
+    needs: release
+    if: needs.release.outputs.published == 'true'
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        alias:
+          - version: v${{ needs.release.outputs.release-version-major }}
+          - version: v${{ needs.release.outputs.release-version-major }}.${{ needs.release.outputs.release-version-minor }}
+
+    steps:
+      - uses: actions/github-script@v2
+        with:
+          script: |
+            const tag = 'tags/${{ matrix.alias.version }}'
+            const repo = {
+              owner: context.repo.owner,
+              repo: context.repo.repo
+            }
+            await github.git.deleteRef({ ...repo, ref: tag }).catch(() => {})
+            await github.git.createRef({ ...repo, ref: `refs/${tag}` , sha: process.env.GITHUB_SHA })

.releaserc

@@ -0,0 +1,35 @@
+{
+  "plugins": [
+    ["@semantic-release/commit-analyzer", {
+      "preset": "conventionalcommits",
+      "releaseRules": [
+        { "breaking": true,   "release": "major" },
+        { "revert": true,     "release": "patch" },
+        { "type": "build",    "release": "patch" },
+        { "type": "docs",     "release": "patch" },
+        { "type": "feat",     "release": "minor" },
+        { "type": "fix",      "release": "patch" },
+        { "type": "perf",     "release": "patch" },
+        { "type": "refactor", "release": "patch" }
+      ]
+    }],
+    ["@semantic-release/release-notes-generator", {
+      "preset": "conventionalcommits",
+      "presetConfig": {
+        "types": [
+          { "type": "build",    "section": "Build",       "hidden": false },
+          { "type": "chore",    "section": "Chores",      "hidden": false },
+          { "type": "ci",       "section": "CI/CD",       "hidden": false },
+          { "type": "docs",     "section": "Docs",        "hidden": false },
+          { "type": "feat",     "section": "Features",    "hidden": false },
+          { "type": "fix",      "section": "Bug Fixes",   "hidden": false },
+          { "type": "perf",     "section": "Performance", "hidden": false },
+          { "type": "refactor", "section": "Refactor",    "hidden": false },
+          { "type": "style",    "section": "Code Style",  "hidden": false },
+          { "type": "test",     "section": "Tests",       "hidden": false }
+        ]
+      }
+    }],
+    "@semantic-release/github"
+  ]
+}

package.json

@@ -0,0 +1,15 @@
+{
+    "private": true,
+    "name": "merge-upstream",
+    "version": "0.0.0-semantically-released",
+    "author": {
+      "name": "lcenchew",
+      "email": "lcenchew@outlook.com",
+      "url": "https://github.com/exions/merge-upstream"
+    },
+    "license": "MIT",
+    "dependencies": {
+    },
+    "devDependencies": {
+    }
+  }