Add `file` input to `build-push-action`

Exposing this configuration would allow Dagster repos w/ multiple code locations to use different Dockerfiles for each code location

dagster-cloud-action/actions/hybrid_branch_deploy/action.yml

Lines 55 to 66 in 3eeebe9

    
               # See https://github.com/docker/build-push-action/ for more info 
        
               - name: Build and push Docker image 
        
                 if: ${{ github.event.pull_request.state != 'closed' }} 
        
                 uses: docker/build-push-action@v3 
        
                 with: 
        
                   context: ${{ fromJson(inputs.location).directory }} 
        
                   push: true 
        
                   tags: "${{ fromJson(inputs.location).registry }}:${{ github.sha }}" 
        
                   labels: | 
        
                     branch=${{ github.head_ref }} 
        
                   cache-from: type=gha 
        
                   cache-to: type=gha,mode=max

	# See https://github.com/docker/build-push-action/ for more info
	- name: Build and push Docker image
	if: ${{ github.event.pull_request.state != 'closed' }}
	uses: docker/build-push-action@v3
	with:
	context: ${{ fromJson(inputs.location).directory }}
	push: true
	tags: "${{ fromJson(inputs.location).registry }}:${{ github.sha }}"
	labels: \|
	branch=${{ github.head_ref }}
	cache-from: type=gha
	cache-to: type=gha,mode=max