ci: remove docker step on main (#951)

We no longer consume these images so lets stop building them.
Additionally we recently rotated some credentials and this step broke.
Rather than fixing it I think we should just remove it since we don't
use the artifacts anymore.

Test Plan: watch CI on main

Author: keegancsmith

.github/workflows/ci.yml

@@ -113,73 +113,3 @@ jobs:
       # Check if the generated code is up-to-date
       - run: .github/workflows/buf-generate-check.sh
 
-  # We build a shared docker image called "zoekt". This is not pushed, but is
-  # used for creating the indexserver and webserver images.
-  docker:
-    if: github.ref == 'refs/heads/main'
-    runs-on: ubuntu-latest
-    needs:
-      - "test"
-      - "shellcheck"
-    steps:
-      - name: checkout
-        uses: actions/checkout@v3
-
-      - name: version
-        id: version
-        run: .github/workflows/docker-version.sh
-
-      - name: docker-meta-webserver
-        id: meta-webserver
-        uses: docker/metadata-action@v3
-        with:
-          images: |
-            sourcegraph/zoekt-webserver
-          tags: |
-            type=ref,event=branch
-            type=ref,event=pr
-            type=semver,pattern={{version}}
-            type=sha
-      - name: docker-meta-indexserver
-        id: meta-indexserver
-        uses: docker/metadata-action@v3
-        with:
-          images: |
-            sourcegraph/zoekt-indexserver
-          tags: |
-            type=ref,event=branch
-            type=ref,event=pr
-            type=semver,pattern={{version}}
-            type=sha
-
-      - name: build-zoekt
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          tags: "zoekt:latest"
-          push: "false"
-          build-args: VERSION=${{ steps.version.outputs.value }}
-
-      - name: Login to Docker Hub
-        uses: docker/login-action@v2
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-
-      - name: build-push-webserver
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          tags: sourcegraph/zoekt-webserver:${{ steps.version.outputs.value }}, ${{ steps.meta-webserver.outputs.tags }}, sourcegraph/zoekt-webserver:latest
-          file: Dockerfile.webserver
-          cache-from: sourcegraph/zoekt-webserver:latest
-          push: true
-
-      - name: build-push-indexserver
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          tags: sourcegraph/zoekt-indexserver:${{ steps.version.outputs.value }}, ${{ steps.meta-indexserver.outputs.tags }}, sourcegraph/zoekt-indexserver:latest
-          file: Dockerfile.indexserver
-          cache-from: sourcegraph/zoekt-indexserver:latest
-          push: true