Don't fail fast in CI

It's useful to see why each build failed and fixing them all in one go,
rather than fixing the problems one by one.

Author: Thomasdezeeuw

.github/workflows/main.yml

@@ -13,6 +13,7 @@ jobs:
     name: Test
     runs-on: ${{ matrix.os }}
     strategy:
+      fail-fast: false
       matrix:
         build: [stable, beta, nightly, macos, windows]
         include:
@@ -55,6 +56,7 @@ jobs:
     name: Check
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         # TODO: add the following targets, currently broken.
         # "x86_64-fuchsia"