chore(ci): don't fail fast for build job

this commit prevents the build job from failing fast (i.e. if '2' in the
stencil_version matrix fails, the rest of the jobs will not fail). this
ought to allow us to root our stencil version-based errors more easily
if an error pertains to a single version

.github/workflows/main.yml

@@ -12,6 +12,7 @@ jobs:
   build:
     name: (stencil-sass with Stencil version ${{ matrix.stencil_version }})
     strategy:
+      fail-fast: false
       matrix:
         # Run with multiple different versions of Stencil in parallel:
         # 1. DEFAULT - uses the version of Stencil written in `package-lock.json`, keeping the same version used by the