Changesets setup + auto-publish to npm (#922)

Closes #905 

## Summary

This PR sets up changesets with the aim to simplify the process of documenting changes committed to the codebase, as well as automating versioning packages and publishing them to npm.

## Changes
- initialised [changesets](https://github.com/changesets/changesets) in the repository
- (separately from this PR) installed [changesets bot](https://github.com/apps/changeset-bot) in the repository (it will check if a submitted PR includes a changeset file and inform if found or not)
- added `.github/workflows/release.yml`: The workflow creates a PR with version bumps and related changelog
files' updates, each time a commit containing changeset
file(s) is added to the main branch. After merging this auto-generated PR, this workflow will also auto-publish the released packages to npm and add git tags.
- added the following scripts to the root `package.json`:
  - `changeset`: should be run to generate changeset files, that describe changes made to the code,
  - `prerelease`: runs linting and testing on packages affected by the changes in a PR
  - `release`: runs `changeset publish` and is used by the `release` workflow then the above-mentioned auto-generated PR is merged to the main branch

.changeset/README.md

@@ -0,0 +1,8 @@
+# Changesets
+
+Hello and welcome! This folder has been automatically generated by `@changesets/cli`, a build tool that works
+with multi-package repos, or single-package repos to help you version and publish your code. You can
+find the full documentation for it [in our repository](https://github.com/changesets/changesets)
+
+We have a quick list of common questions to get you started engaging with this project in
+[our documentation](https://github.com/changesets/changesets/blob/main/docs/common-questions.md)

.changeset/config.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "https://unpkg.com/@changesets/config@2.3.0/schema.json",
+  "changelog": [
+    "@changesets/changelog-github",
+    { "repo": "datopian/portaljs" }
+  ],
+  "commit": false,
+  "fixed": [],
+  "linked": [],
+  "access": "restricted",
+  "baseBranch": "main",
+  "updateInternalDependencies": "patch",
+  "ignore": []
+}

.github/workflows/release.yml

@@ -0,0 +1,39 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - main
+
+concurrency: release-${{ github.ref }}
+
+jobs:
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Repo
+        uses: actions/checkout@v3
+
+      - name: Setup Node.js 16.x
+        uses: actions/setup-node@v3
+        with:
+          node-version: 16.x
+
+      - name: Install Dependencies
+        run: npm ci
+
+      - name: Create Release Pull Request or Publish to npm
+        id: changesets
+        uses: changesets/action@v1
+        with:
+          publish: npm run release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
+
+      # - name: Send a Discord notification if a publish happens
+      #   if: steps.changesets.outputs.published == 'true'
+      #   uses: Ilshidur/action-discord@0.3.2
+      #   with:
+      #     args: 'The project {{ EVENT_PAYLOAD.repository.full_name }} has been deployed.'

CONTRIBUTING.md

@@ -13,7 +13,7 @@ Structure:
   - **dataset-frictionless**: Example utilizing a frictionless dataset as an example
 - **site**: the website for the project, with a landing page and the docs
 - **packages**:
-    - **portaljs-components**: the library of components for creating a data portal
+  - **portaljs-components**: the library of components for creating a data portal
 
 ## How to contribute
 
@@ -26,10 +26,11 @@ If you'd like to work on one of the issues you can:
 3. Clone the forked repository to your machine.
 4. Create a feature branch (e.g. `50-update-readme`, where `50` is the number of the related issue).
 5. Commit your changes to the feature branch.
-6. Push the feature branch to your forked repository.
-7. Create a Pull Request against the original repository.
+6. Add changeset file describing the changes. (See section below)
+7. Push the feature branch to your forked repository.
+8. Create a Pull Request against the original repository.
    - add a short description of the changes included in the PR
-8. Address review comments if requested by our demanding reviewers 😜.
+9. Address review comments if requested by our demanding reviewers 😜.
 
 If you have an idea for improvement, and it doesn't have a corresponding issue yet, simply submit a new one.
 
@@ -62,6 +63,7 @@ or you can use just:
 nx <target> <project>
 # e.g. npx nx serve ckan
 ```
+
 if you have the `nx` binary installed globally in your machine
 
 #### Running multiple tasks
@@ -109,7 +111,7 @@ To check code formatting in selected projects:
 
 ```sh
 npx nx format:check --projects=<array of projects>
-# npx nx format:check --projects=ckan,dataset-frictionless 
+# npx nx format:check --projects=ckan,dataset-frictionless
 ```
 
 To check code formatting in all projects:
@@ -124,7 +126,7 @@ To fix code formatting in selected projects:
 
 ```sh
 npx nx format:write --projects=<array projects>
-# npx nx format:write --projects=ckan,dataset-frictionless 
+# npx nx format:write --projects=ckan,dataset-frictionless
 ```
 
 To fix formatting in all projects:
@@ -174,3 +176,23 @@ To learn more see this [offical docs page](https://nx.dev/reference/nx-json).
 Each project also has it's own configuration file - `project.json`, where you can define and configure it's targets (and more).
 
 To learn more see this [offical docs page](https://nx.dev/reference/project-configuration).
+
+## Changesets and publishing packages
+
+> This monorepo is set up with changesets versioning tool. See their [github repository](https://github.com/changesets/changesets) to learn more.
+
+### What are Changesets?
+
+Changesets are files that describe the intention of a contributor to bump a version of the package according to their changes. Changeset file holds two key bits of information: a version type (following semver), and change information to be added to a changelog.
+
+### Adding changesets
+
+In the root directory of the repo, run:
+
+```
+npx changeset
+```
+
+Select the package that has been changed, the semver version that should be bumped with it and a description of your changes. Please make sure to add the most accurate but also concise information.
+
+To learn about semantic versioning standards see [this semver doc page](https://semver.org/).