Improve on "Add Windows to the mix" (#52)

* Support more OTP+Windows versions (try to bridge the gap with gleam-lang/setup-erlang that seems to support pre-21 versions)
* Merge ci.yml and test.yml
* Add Elixir to the Windows mix
* Hopefully improve error/warning messages
* Adapt the doc.s to the current reality
* Add option version-type (loose by default, for compatibility)

.github/workflows/action.yml

@@ -0,0 +1,42 @@
+---
+name: action
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  check_integrity:
+    name: Expected local npm actions
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: '12'
+      - run: npm install -g npm
+      - run: npm install
+      - run: npm run build
+      - run: npm run format
+      - run: npm install -g markdownlint-cli
+      - run: npm run markdownlint
+      - run: npm run shellcheck
+      - run: npm run yamllint
+      - run: npm run jslint
+      - run: npm run licenses
+      - name: Check if build left artifacts
+        run: git diff --exit-code
+
+  unit_test:
+    name: Unit tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with: {node-version: '12'}
+      - run: npm ci
+      - run: npm test