Disable 'fail-fast' for master and tag builds on CI (#372)

.github/workflows/ci.yml

@@ -13,6 +13,14 @@ jobs:
     runs-on: ${{ matrix.config.os }}
     timeout-minutes: 120
     strategy:
+      # Always run master branch builds to completion. This allows the cache to
+      # stay mostly up-to-date in situations where a single job fails due to
+      # e.g. a flaky test.
+      # Don't fast-fail on tag build because publishing binaries shouldn't be
+      # prevented if 'cargo publish' fails (which can be a false negative).
+      fail-fast:
+        ${{ github.event_name == 'pull_request' || (github.ref !=
+        'refs/heads/master' && !startsWith(github.ref, 'refs/tags/')) }}
       matrix:
         config:
           - os: macOS-latest