Pin oven-sh/setup-bun to full commit SHA

Required by repo policy that all actions must be pinned to a full-length commit SHA.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: kriszyp

.github/workflows/integration-tests.yml

@@ -151,7 +151,7 @@ jobs:
           package-manager-cache: false
 
       - name: Setup Bun
-        uses: oven-sh/setup-bun@v2
+        uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2
 
       - name: Download build artifacts
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
@@ -261,7 +261,7 @@ jobs:
           package-manager-cache: false
 
       - name: Setup Bun
-        uses: oven-sh/setup-bun@v2
+        uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2
 
       - name: Download build artifacts
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1