ci: use blacksmith runners for arm64 builds

Author: auxesis

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
       matrix:
         build:
           - { os: blacksmith-16vcpu-ubuntu-2204, docker_platform: linux/amd64, rust_target: "x86_64-unknown-linux-gnu",  cache-provider: buildjet }
-          - { os: linux-arm64-public,          docker_platform: linux/arm64, rust_target: "aarch64-unknown-linux-gnu", cache-provider: github }
+          - { os: blacksmith-16vcpu-ubuntu-2404-arm, docker_platform: linux/arm64, rust_target: "aarch64-unknown-linux-gnu", cache-provider: github }
     env:
       CS_ZEROKMS_HOST: https://us-east-1.aws.zerokms.cipherstashmanaged.net
       CS_CTS_HOST: https://ap-southeast-2.aws.cts.cipherstashmanaged.net
@@ -103,7 +103,7 @@ jobs:
 
   merge:
     name: Publish multi-platform image
-    runs-on: linux-arm64-public
+    runs-on: blacksmith-16vcpu-ubuntu-2404-arm
     needs:
       - build
     steps: