Speedup win testing on Appveyor.

Appveyor is one of the slowest CI, here we enable fast-fail to
make sure if one of the matrix element fail we cancel the others.

Author: Carreau

.github/workflows/windows-testing.yml

@@ -38,7 +38,7 @@ jobs:
           conda activate zarr-env
           python -m pip install --upgrade pip
           python -m pip install -U pip setuptools wheel
-          python -m pip install -rrequirements_dev_minimal.txt numpy${{ matrix.numpy_version}} -rrequirements_dev_optional.txt
+          python -m pip install -r requirements_dev_numpy.txt -r requirements_dev_minimal.txt -r requirements_dev_optional.txt
           python -m pip install -e .
           python -m pip freeze
       - name: Run Tests

appveyor.yml

@@ -17,7 +17,6 @@ environment:
     ZARR_TEST_ABS: 1
 
   matrix:
-
     - PYTHON: "C:\\Python36-x64"
       PYTHON_VERSION: "3.6"
 
@@ -45,3 +44,6 @@ test_script:
 
 after_test:
   - '"%EMULATOR_LOC%" stop'
+  
+matrix:
+  fast_finish: true