chore: add release-it

New releases are created by pushing a tag with semantic versioning (v*)
...

.github/workflows/release.yml

@@ -0,0 +1,16 @@
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - run: yarn install
+      - run: yarn run release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.release-it.json

@@ -0,0 +1,22 @@
+{
+  "git": {
+    "commitMessage": "chore: release ${version}"
+  },
+  "github": {
+    "release": true
+  },
+  "npm": {
+    "publish": false
+  },
+  "plugins": {
+    "@release-it/bumper": {
+      "out": [
+        "package.json",
+        {
+          "file": "publiccode.yml",
+          "path": "softwareVersion"
+        }
+      ]
+    }
+  }
+}