add -c fastbuild to bazel CI build/test commands

Author: j2kun

.github/workflows/build_and_test.yml

@@ -26,8 +26,8 @@ jobs:
 
       - name: "Run `bazel build`"
         run: |
-          bazel build //...
+          bazel build -c fastbuild //...
 
       - name: "Run `bazel test`"
         run: |
-          bazel test //...
+          bazel test -c fastbuild //...