Don't run the publish workflow on PR. (#76)

It takes foooorever and we have a separate check.

.github/workflows/publish.yml

@@ -6,14 +6,10 @@ name: Publish Docker Image
 # documentation.
 
 on:
-    schedule:
-        - cron: "26 7 * * *"
     push:
         branches: ["main"]
         # Publish semver tags as releases.
         tags: ["v*.*.*"]
-    pull_request:
-        branches: ["main"]
 
 env:
     # Use docker.io for Docker Hub if empty
@@ -35,10 +31,9 @@ jobs:
             - name: Checkout repository
               uses: actions/checkout@v3
 
-            # Install the cosign tool except on PR
+            # Install the cosign tool
             # https://github.com/sigstore/cosign-installer
             - name: Install cosign
-              if: github.event_name != 'pull_request'
               uses: sigstore/cosign-installer@6e04d228eb30da1757ee4e1dd75a0ec73a653e06 #v3.1.1
               with:
                   cosign-release: "v2.1.1"
@@ -49,10 +44,9 @@ jobs:
             - name: Set up Docker Buildx
               uses: docker/setup-buildx-action@f95db51fddba0c2d1ec667646a06c2ce06100226 # v3.0.0
 
-            # Login against a Docker registry except on PR
+            # Login against a Docker registry
             # https://github.com/docker/login-action
             - name: Log into registry ${{ env.REGISTRY }}
-              if: github.event_name != 'pull_request'
               uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.0.0
               with:
                   registry: ${{ env.REGISTRY }}
@@ -74,20 +68,18 @@ jobs:
               uses: docker/build-push-action@0565240e2d4ab88bba5387d719585280857ece09 # v5.0.0
               with:
                   context: .
-                  push: ${{ github.event_name != 'pull_request' }}
                   tags: ${{ steps.meta.outputs.tags }}
                   labels: ${{ steps.meta.outputs.labels }}
                   platforms: linux/amd64,linux/arm64
                   cache-from: type=gha
                   cache-to: type=gha,mode=max
 
-            # Sign the resulting Docker image digest except on PRs.
+            # Sign the resulting Docker image digest
             # This will only write to the public Rekor transparency log when the Docker
             # repository is public to avoid leaking data.  If you would like to publish
             # transparency data even for private images, pass --force to cosign below.
             # https://github.com/sigstore/cosign
             - name: Sign the published Docker image
-              if: ${{ github.event_name != 'pull_request' }}
               env:
                   # https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
                   TAGS: ${{ steps.meta.outputs.tags }}