ci: add 'fail-fast' to false

The following commit adds the strategy option to not `fail-fast` during
the matrix so all operating systems can build without cancelling
eachother.

Signed-off-by: vince-fugnitto <vincent.fugnitto@ericsson.com>

.github/workflows/build.yml

@@ -17,6 +17,7 @@ jobs:
     name: ${{ matrix.os }}, Node.js v${{ matrix.node }}, Python ${{ matrix.python }}
 
     strategy:
+      fail-fast: false
       matrix:
         os: [windows-2019, ubuntu-18.04, macos-10.15]
         node: ['12.x']