Use pip install as workaround when make install doesn't work (#1585)

* Don't use editable install for vercel build

Fixes issue with `pip=21.3`, inspired by commit from
zarr-developers/zarr-python@7ee2ded.

* Mention how Windows users can install PyGMT in editable mode

So that Windows users without `make`
can install an editable version of PyGMT locally.

Author: weiji14

doc/contributing.md

@@ -197,7 +197,8 @@ copy the commands you want to run.
 To install the current source code into your testing environment, run:
 
 ```bash
-make install
+make install  # on Linux/macOS
+pip install --no-deps -e .  # on Windows
 ```
 
 This installs your project in *editable* mode, meaning that changes made to the source

package.json

@@ -1,7 +1,7 @@
 {
   "scripts": {
     "build:miniconda": "curl -o ~/miniconda.sh https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh && bash ~/miniconda.sh -b -p $HOME/miniconda",
-    "build:pygmt": "conda install mamba -c conda-forge -y && mamba env create -f environment.yml && source activate pygmt && make install",
+    "build:pygmt": "conda install mamba -c conda-forge -y && mamba env create -f environment.yml && source activate pygmt && pip install --no-deps .",
     "build:docs": "source activate pygmt && cd doc && make all && mv _build/html ../public",
     "build": "export PATH=$HOME/miniconda/bin:$PATH && export GMT_DATA_SERVER=https://oceania.generic-mapping-tools.org && npm run build:miniconda && npm run build:pygmt && npm run build:docs"
   }