Update to new standard linux builder images

Author: SeanTAllen

.github/workflows/breakage-against-linux-ponyc-latest.yml

@@ -12,7 +12,7 @@ jobs:
     name: Verify main against the latest ponyc on Linux
     runs-on: ubuntu-latest
     container:
-      image: ghcr.io/ponylang/shared-docker-ci-x86-64-unknown-linux-builder:latest
+      image: ghcr.io/ponylang/shared-docker-ci-standard-builder:nightly
     steps:
       - uses: actions/checkout@v4.1.1
       - name: Test

.github/workflows/nightlies.yml

@@ -50,7 +50,7 @@ jobs:
     name: Build and upload x86-64-unknown-linux-nightly to Cloudsmith
     runs-on: ubuntu-latest
     container:
-      image: ghcr.io/ponylang/shared-docker-ci-x86-64-unknown-linux-builder:release
+      image: ghcr.io/ponylang/shared-docker-ci-standard-builder:release
     steps:
       - uses: actions/checkout@v4.1.1
       - name: Build and upload

.github/workflows/pr.yml

@@ -47,7 +47,7 @@ jobs:
     name: x86_64 Linux
     runs-on: ubuntu-latest
     container:
-      image: ghcr.io/ponylang/shared-docker-ci-x86-64-unknown-linux-builder:release
+      image: ghcr.io/ponylang/shared-docker-ci-standard-builder:release
     steps:
       - uses: actions/checkout@v4.1.1
       - name: Test with most recent ponyc release

.github/workflows/release.yml

@@ -64,7 +64,7 @@ jobs:
     needs:
       - pre-artefact-creation
     container:
-      image: ghcr.io/ponylang/shared-docker-ci-x86-64-unknown-linux-builder:release
+      image: ghcr.io/ponylang/shared-docker-ci-standard-builder:release
     steps:
       - uses: actions/checkout@v4.1.1
       - name: Build and upload