fix: add release-assets.githubusercontent.com to allowed domains (GoogleCloudPlatform#713)

Author: maemayve

.github/workflows/conformance.yml

@@ -26,6 +26,7 @@ jobs:
             objects.githubusercontent.com:443
             proxy.golang.org:443
             registry.npmjs.org:443
+            release-assets.githubusercontent.com:443
             storage.googleapis.com:443
             sum.golang.org:443
 

.github/workflows/unit.yml

@@ -25,6 +25,7 @@ jobs:
             github.com:443
             objects.githubusercontent.com:443
             registry.npmjs.org:443
+            release-assets.githubusercontent.com:443
 
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2