Revert "Bump dart-lang/setup-dart from 1.4.0 to 1.5.0 (#95)" (#99)

This reverts commit 4684409.

Author: devoncarew

.github/workflows/test-package.yml

@@ -23,7 +23,7 @@ jobs:
         sdk: [dev]
     steps:
       - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
-      - uses: dart-lang/setup-dart@d6a63dab3335f427404425de0fbfed4686d93c4f
+      - uses: dart-lang/setup-dart@a57a6c04cf7d4840e88432aad6281d1e125f0d46
         with:
           sdk: ${{ matrix.sdk }}
       - id: install
@@ -49,7 +49,7 @@ jobs:
         sdk: [2.18.0, dev]
     steps:
       - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
-      - uses: dart-lang/setup-dart@d6a63dab3335f427404425de0fbfed4686d93c4f
+      - uses: dart-lang/setup-dart@a57a6c04cf7d4840e88432aad6281d1e125f0d46
         with:
           sdk: ${{ matrix.sdk }}
       - id: install