Revert the migration from Vercel App to Vercel action (#973)

* Revert "Disable pull_request_target for the vercel action (#969)"

This reverts commit f455c31.

* Revert "Use Vercel action for continuous documentation (#964)"

This reverts commit 17133d1.

MAINTENANCE.md

@@ -47,7 +47,7 @@ conda and the `Makefile` to run the tests and checks.
 
 ### GitHub Actions
 
-There are 6 configuration files located in `.github/workflows`:
+There are 5 configuration files located in `.github/workflows`:
 
 1. `style_checks.yaml` (Code lint and style checks)
 
@@ -84,19 +84,16 @@ This workflow is ran to publish wheels to PyPI and TestPyPI (for testing only).
 Archives will be pushed to TestPyPI on every commit to the *master* branch and
 tagged releases, and to PyPI for tagged releases only.
 
-6. `continuous-documentation.yml` (Deploy documentation to Vercel for preview)
-
-This workflow builds and deploys the documentation in Pull Requests to Vercel,
-to make it easier to preview documentation changes.
 
 ## Continuous Documentation
 
-We use a cloud platform service called [Vercel](https://vercel.com/) via
-[vercel-action](https://github.com/marketplace/actions/vercel-action) to
-preview changes made to our documentation website every time we make a commit
-in a pull request. The workflow `continuous-documentation.yml` builds and
-deploys the documentation to Vercel. The vercel bot will automatically make a
-comment with a URL to preview the deployed documentation for that pull request.
+We use the [Vercel for GitHub](https://github.com/apps/vercel) App to preview changes
+made to our documentation website every time we make a commit in a pull request.
+The service has a configuration file `vercel.json`, with a list of options to
+change the default behaviour at https://vercel.com/docs/configuration.
+The actual script `package.json` is used by Vercel to install the necessary packages,
+build the documentation, copy the files to a 'public' folder and deploy that to the web,
+see https://vercel.com/docs/build-step.
 
 ## Making a Release
 

package.json

@@ -0,0 +1,8 @@
+{
+  "scripts": {
+    "build:miniconda": "curl -o ~/miniconda.sh https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh && bash ~/miniconda.sh -b -p $HOME/miniconda",
+    "build:pygmt": "conda install mamba -c conda-forge -y && mamba env create -f environment.yml && source activate pygmt && make install",
+    "build:docs": "source activate pygmt && cd doc && make all && mv _build/html ../public",
+    "build": "export PATH=$HOME/miniconda/bin:$PATH && npm run build:miniconda && npm run build:pygmt && npm run build:docs"
+  }
+}

vercel.json

@@ -0,0 +1,6 @@
+{
+  "github": {
+    "silent": true
+  },
+  "public": true
+}