chore: allow manual trigger of builds

Adds the workflow_dispatch trigger to manually trigger docker builds
from the actions menu.

.github/workflows/docker-image.yml

@@ -5,6 +5,7 @@ name: Create and publish a Docker image
 on:
   push:
     branches: ['release']
+  workflow_dispatch:
 
 # Defines two custom environment variables for the workflow. These are used for the Container registry domain, and a name for the Docker image that this workflow builds.
 env:
@@ -20,7 +21,7 @@ jobs:
       contents: read
       packages: write
       attestations: write
-      # 
+      #
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -48,12 +49,12 @@ jobs:
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
-      
-      # This step generates an artifact attestation for the image, which is an unforgeable statement about where and how it was built. It increases supply chain security for people who consume the image. For more information, see "[AUTOTITLE](/actions/security-guides/using-artifact-attestations-to-establish-provenance-for-builds)." 
+
+      # This step generates an artifact attestation for the image, which is an unforgeable statement about where and how it was built. It increases supply chain security for people who consume the image. For more information, see "[AUTOTITLE](/actions/security-guides/using-artifact-attestations-to-establish-provenance-for-builds)."
       - name: Generate artifact attestation
         uses: actions/attest-build-provenance@v1
         with:
           subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}
           subject-digest: ${{ steps.push.outputs.digest }}
           push-to-registry: true
-      
+