Makefile: update bfirsh/redoc to 1.14.0, and fix swagger warnings

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Makefile

@@ -264,7 +264,7 @@ swagger-docs: ## preview the API documentation
 	@docker run --rm -v $(PWD)/api/swagger.yaml:/usr/share/nginx/html/swagger.yaml \
 		-e 'REDOC_OPTIONS=hide-hostname="true" lazy-rendering' \
 		-p $(SWAGGER_DOCS_PORT):80 \
-		bfirsh/redoc:1.6.2
+		bfirsh/redoc:1.14.0
 
 .PHONY: buildx
 ifdef USE_BUILDX

api/swagger.yaml

@@ -746,6 +746,7 @@ definitions:
     description: |
       Health stores information about the container's healthcheck results.
     type: "object"
+    x-nullable: true
     properties:
       Status:
         description: |
@@ -771,13 +772,13 @@ definitions:
         description: |
           Log contains the last few results (oldest first)
         items:
-          x-nullable: true
           $ref: "#/definitions/HealthcheckResult"
 
   HealthcheckResult:
     description: |
       HealthcheckResult stores information about a single run of a healthcheck probe
     type: "object"
+    x-nullable: true
     properties:
       Start:
         description: |
@@ -4217,6 +4218,7 @@ definitions:
       ContainerState stores container's running state. It's part of ContainerJSONBase
       and will be returned by the "inspect" command.
     type: "object"
+    x-nullable: true
     properties:
       Status:
         description: |
@@ -4274,7 +4276,6 @@ definitions:
         type: "string"
         example: "2020-01-06T09:07:59.461876391Z"
       Health:
-        x-nullable: true
         $ref: "#/definitions/Health"
 
   SystemVersion:
@@ -5787,7 +5788,6 @@ paths:
                 items:
                   type: "string"
               State:
-                x-nullable: true
                 $ref: "#/definitions/ContainerState"
               Image:
                 description: "The container's image ID"