Add semantic-release

[luisherranz]

Add semantic-release with the default config we used to have in the past. Something like:

{
  "verifyConditions": [
    "@semantic-release/changelog",
    "@semantic-release/github",
    "@semantic-release/npm",
    "@semantic-release/git"
  ],
  "prepare": [
    "@semantic-release/changelog",
    "@semantic-release/npm",
    "@semantic-release/git"
  ],
  "publish": [
    "@semantic-release/github",
    "@semantic-release/npm"
  ],
  "success": ["@semantic-release/github"],
  "fail": ["@semantic-release/github"],
  "branch": "master"
}